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Ingy döt Net 2023-07-01 11:58:00 -04:00
parent 7387c8f97b
commit cb5bb5e222
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---
from: http://rosettacode.org/wiki/Additive_primes
note: Prime Numbers

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;Definitions
In mathematics, '''additive primes''' are prime numbers for which the sum of their decimal digits are also primes.
;Task
Write a program to determine (and show here) all '''additive primes''' less than '''500'''.
Optionally, show the '''number''' of additive primes.
;Also see:
:*   the OEIS entry:   [https://oeis.org/A046704 A046704 additive primes].
:*   the prime-numbers entry:   [https://prime-numbers.info/list/first-100-additive-primes additive primes].
:*   the geeks for geeks entry: [https://www.geeksforgeeks.org/additive-prime-number/ additive prime number].
:*   the prime-numbers fandom: [https://prime-numbers.fandom.com/wiki/Additive_Primes additive primes].
<br><br>

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F is_prime(a)
I a == 2
R 1B
I a < 2 | a % 2 == 0
R 0B
L(i) (3 .. Int(sqrt(a))).step(2)
I a % i == 0
R 0B
R 1B
F digit_sum(=n)
V sum = 0
L n > 0
sum += n % 10
n I/= 10
R sum
V additive_primes = 0
L(i) 2..499
I is_prime(i) & is_prime(digit_sum(i))
additive_primes++
print(i, end' )
print("\nFound "additive_primes additive primes less than 500)

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/* ARM assembly AARCH64 Raspberry PI 3B or android 64 bits */
/* program additivePrime64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ MAXI, 500
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessResult: .asciz "Prime : @ \n"
szMessCounter: .asciz "Number found : @ \n"
szCarriageReturn: .asciz "\n"
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
sZoneConv: .skip 24
TablePrime: .skip 8 * MAXI
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: // entry of program
bl createArrayPrime
mov x5,x0 // prime number
ldr x4,qAdrTablePrime // address prime table
mov x10,#0 // init counter
mov x6,#0 // indice
1:
ldr x2,[x4,x6,lsl #3] // load prime
mov x9,x2 // save prime
mov x7,#0 // init digit sum
mov x1,#10 // divisor
2: // begin loop
mov x0,x2 // dividende
udiv x2,x0,x1
msub x3,x2,x1,x0 // compute remainder
add x7,x7,x3 // add digit to digit sum
cmp x2,#0 // quotient null ?
bne 2b // no -> comppute other digit
mov x8,#1 // indice
4: // prime search loop
cmp x8,x5 // maxi ?
bge 5f // yes
ldr x0,[x4,x8,lsl #3] // load prime
cmp x0,x7 // prime >= digit sum ?
add x0,x8,1
csel x8,x0,x8,lt // no -> increment indice
blt 4b // and loop
bne 5f // >
mov x0,x9 // equal
bl displayPrime
add x10,x10,#1 // increment counter
5:
add x6,x6,#1 // increment first indice
cmp x6,x5 // maxi ?
blt 1b // and loop
mov x0,x10 // number counter
ldr x1,qAdrsZoneConv
bl conversion10 // call décimal conversion
ldr x0,qAdrszMessCounter
ldr x1,qAdrsZoneConv // insert conversion in message
bl strInsertAtCharInc
bl affichageMess // display message
100: // standard end of the program
mov x0, #0 // return code
mov x8, #EXIT // request to exit program
svc #0 // perform the system call
qAdrszCarriageReturn: .quad szCarriageReturn
qAdrszMessResult: .quad szMessResult
qAdrszMessCounter: .quad szMessCounter
qAdrTablePrime: .quad TablePrime
/******************************************************************/
/* créate prime array */
/******************************************************************/
createArrayPrime:
stp x1,lr,[sp,-16]! // save registres
ldr x4,qAdrTablePrime // address prime table
mov x0,#1
str x0,[x4] // store 1 in array
mov x0,#2
str x0,[x4,#8] // store 2 in array
mov x0,#3
str x0,[x4,#16] // store 3 in array
mov x5,#3 // prine counter
mov x7,#5 // first number to test
1:
mov x6,#1 // indice
2:
mov x0,x7 // dividende
ldr x1,[x4,x6,lsl #3] // load divisor
udiv x2,x0,x1
msub x3,x2,x1,x0 // compute remainder
cmp x3,#0 // null remainder ?
beq 4f // yes -> end loop
cmp x2,x1 // quotient < divisor
bge 3f
str x7,[x4,x5,lsl #3] // dividende is prime store in array
add x5,x5,#1 // increment counter
b 4f // and end loop
3:
add x6,x6,#1 // else increment indice
cmp x6,x5 // maxi ?
blt 2b // no -> loop
4:
add x7,x7,#2 // other odd number
cmp x7,#MAXI // maxi ?
blt 1b // no -> loop
mov x0,x5 // return counter
100:
ldp x1,lr,[sp],16 // restaur des 2 registres
ret
/******************************************************************/
/* Display prime table elements */
/******************************************************************/
/* x0 contains the prime */
displayPrime:
stp x1,lr,[sp,-16]! // save registres
ldr x1,qAdrsZoneConv
bl conversion10 // call décimal conversion
ldr x0,qAdrszMessResult
ldr x1,qAdrsZoneConv // insert conversion in message
bl strInsertAtCharInc
bl affichageMess // display message
100:
ldp x1,lr,[sp],16 // restaur des 2 registres
ret
qAdrsZoneConv: .quad sZoneConv
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"

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BEGIN # find additive primes - primes whose digit sum is also prime #
# sieve the primes to max prime #
PR read "primes.incl.a68" PR
[]BOOL prime = PRIMESIEVE 499;
# find the additive primes #
INT additive count := 0;
FOR n TO UPB prime DO
IF prime[ n ] THEN
# have a prime #
INT digit sum := 0;
INT v := n;
WHILE v > 0 DO
digit sum +:= v MOD 10;
v OVERAB 10
OD;
IF prime( digit sum ) THEN
# the digit sum is prime #
print( ( " ", whole( n, -3 ) ) );
IF ( additive count +:= 1 ) MOD 20 = 0 THEN print( ( newline ) ) FI
FI
FI
OD;
print( ( newline, "Found ", whole( additive count, 0 ), " additive primes below ", whole( UPB prime + 1, 0 ), newline ) )
END

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begin % find some additive primes - primes whose digit sum is also prime %
% sets p( 1 :: n ) to a sieve of primes up to n %
procedure Eratosthenes ( logical array p( * ) ; integer value n ) ;
begin
p( 1 ) := false; p( 2 ) := true;
for i := 3 step 2 until n do p( i ) := true;
for i := 4 step 2 until n do p( i ) := false;
for i := 3 step 2 until truncate( sqrt( n ) ) do begin
integer ii; ii := i + i;
if p( i ) then for pr := i * i step ii until n do p( pr ) := false
end for_i ;
end Eratosthenes ;
integer MAX_NUMBER;
MAX_NUMBER := 500;
begin
logical array prime( 1 :: MAX_NUMBER );
integer aCount;
% sieve the primes to MAX_NUMBER %
Eratosthenes( prime, MAX_NUMBER );
% find the primes that are additive primes %
aCount := 0;
for i := 1 until MAX_NUMBER - 1 do begin
if prime( i ) then begin
integer dSum, v;
v := i;
dSum := 0;
while v > 0 do begin
dSum := dSum + v rem 10;
v := v div 10
end while_v_gt_0 ;
if prime( dSum ) then begin
writeon( i_w := 4, s_w := 0, " ", i );
aCount := aCount + 1;
if aCount rem 20 = 0 then write()
end if_prime_dSum
end if_prime_i
end for_i ;
write( i_w := 1, s_w := 0, "Found ", aCount, " additive primes below ", MAX_NUMBER )
end
end.

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((+(4/10)P)P)/P(~PP.×P)/P1500

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/* ARM assembly Raspberry PI */
/* program additivePrime.s */
/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/* for constantes see task include a file in arm assembly */
/************************************/
/* Constantes */
/************************************/
.include "../constantes.inc"
.equ MAXI, 500
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessResult: .asciz "Prime : @ \n"
szMessCounter: .asciz "Number found : @ \n"
szCarriageReturn: .asciz "\n"
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
sZoneConv: .skip 24
TablePrime: .skip 4 * MAXI
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: @ entry of program
bl createArrayPrime
mov r5,r0 @ prime number
ldr r4,iAdrTablePrime @ address prime table
mov r10,#0 @ init counter
mov r6,#0 @ indice
1:
ldr r2,[r4,r6,lsl #2] @ load prime
mov r9,r2 @ save prime
mov r7,#0 @ init digit sum
mov r1,#10 @ divisor
2: @ begin loop
mov r0,r2 @ dividende
bl division
add r7,r7,r3 @ add digit to digit sum
cmp r2,#0 @ quotient null ?
bne 2b @ no -> comppute other digit
mov r8,#1 @ indice
4: @ prime search loop
cmp r8,r5 @ maxi ?
bge 5f @ yes
ldr r0,[r4,r8,lsl #2] @ load prime
cmp r0,r7 @ prime >= digit sum ?
addlt r8,r8,#1 @ no -> increment indice
blt 4b @ and loop
bne 5f @ >
mov r0,r9 @ equal
bl displayPrime
add r10,r10,#1 @ increment counter
5:
add r6,r6,#1 @ increment first indice
cmp r6,r5 @ maxi ?
blt 1b @ and loop
mov r0,r10 @ number counter
ldr r1,iAdrsZoneConv
bl conversion10 @ call décimal conversion
ldr r0,iAdrszMessCounter
ldr r1,iAdrsZoneConv @ insert conversion in message
bl strInsertAtCharInc
bl affichageMess @ display message
100: @ standard end of the program
mov r0, #0 @ return code
mov r7, #EXIT @ request to exit program
svc #0 @ perform the system call
iAdrszCarriageReturn: .int szCarriageReturn
iAdrszMessResult: .int szMessResult
iAdrszMessCounter: .int szMessCounter
iAdrTablePrime: .int TablePrime
/******************************************************************/
/* créate prime array */
/******************************************************************/
createArrayPrime:
push {r1-r7,lr} @ save registers
ldr r4,iAdrTablePrime @ address prime table
mov r0,#1
str r0,[r4] @ store 1 in array
mov r0,#2
str r0,[r4,#4] @ store 2 in array
mov r0,#3
str r0,[r4,#8] @ store 3 in array
mov r5,#3 @ prine counter
mov r7,#5 @ first number to test
1:
mov r6,#1 @ indice
2:
mov r0,r7 @ dividende
ldr r1,[r4,r6,lsl #2] @ load divisor
bl division
cmp r3,#0 @ null remainder ?
beq 3f @ yes -> end loop
cmp r2,r1 @ quotient < divisor
strlt r7,[r4,r5,lsl #2] @ dividende is prime store in array
addlt r5,r5,#1 @ increment counter
blt 3f @ and end loop
add r6,r6,#1 @ else increment indice
cmp r6,r5 @ maxi ?
blt 2b @ no -> loop
3:
add r7,#2 @ other odd number
cmp r7,#MAXI @ maxi ?
blt 1b @ no -> loop
mov r0,r5 @ return counter
100:
pop {r1-r7,pc}
/******************************************************************/
/* Display prime table elements */
/******************************************************************/
/* r0 contains the prime */
displayPrime:
push {r1,lr} @ save registers
ldr r1,iAdrsZoneConv
bl conversion10 @ call décimal conversion
ldr r0,iAdrszMessResult
ldr r1,iAdrsZoneConv @ insert conversion in message
bl strInsertAtCharInc
bl affichageMess @ display message
100:
pop {r1,pc}
iAdrsZoneConv: .int sZoneConv
/***************************************************/
/* ROUTINES INCLUDE */
/***************************************************/
.include "../affichage.inc"

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# syntax: GAWK -f ADDITIVE_PRIMES.AWK
BEGIN {
start = 1
stop = 500
for (i=start; i<=stop; i++) {
if (is_prime(i) && is_prime(sum_digits(i))) {
printf("%4d%1s",i,++count%10?"":"\n")
}
}
printf("\nAdditive primes %d-%d: %d\n",start,stop,count)
exit(0)
}
function is_prime(x, i) {
if (x <= 1) {
return(0)
}
for (i=2; i<=int(sqrt(x)); i++) {
if (x % i == 0) {
return(0)
}
}
return(1)
}
function sum_digits(n, i,sum) {
for (i=1; i<=length(n); i++) {
sum += substr(n,i,1)
}
return(sum)
}

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;;; find some additive primes - primes whose digit sum is also prime
;;; Library: Action! Sieve of Eratosthenes
INCLUDE "H6:SIEVE.ACT"
PROC Main()
DEFINE MAX_PRIME = "500"
BYTE ARRAY primes(MAX_PRIME)
CARD n, digitSum, v, count
Sieve(primes,MAX_PRIME)
count = 0
FOR n = 1 TO MAX_PRIME - 1 DO
IF primes( n ) THEN
digitSum = 0
v = n
WHILE v > 0 DO
digitSum ==+ v MOD 10
v ==/ 10
OD
IF primes( digitSum ) THEN
IF n < 100 THEN
Put(' )
IF n < 10 THEN Put(' ) FI
FI
Put(' )PrintI( n )
count ==+ 1
IF count MOD 20 = 0 THEN PutE() FI
FI
FI
OD
PutE()Print( "Found " )PrintI( count )Print( " additive primes below " )PrintI( MAX_PRIME + 1 )PutE()
RETURN

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with Ada.Text_Io;
procedure Additive_Primes is
Last : constant := 499;
Columns : constant := 12;
type Prime_List is array (2 .. Last) of Boolean;
function Get_Primes return Prime_List is
Prime : Prime_List := (others => True);
begin
for P in Prime'Range loop
if Prime (P) then
for N in 2 .. Positive'Last loop
exit when N * P not in Prime'Range;
Prime (N * P) := False;
end loop;
end if;
end loop;
return Prime;
end Get_Primes;
function Sum_Of (N : Natural) return Natural is
Image : constant String := Natural'Image (N);
Sum : Natural := 0;
begin
for Char of Image loop
Sum := Sum + (if Char in '0' .. '9'
then Natural'Value ("" & Char)
else 0);
end loop;
return Sum;
end Sum_Of;
package Natural_Io is new Ada.Text_Io.Integer_Io (Natural);
use Ada.Text_Io, Natural_Io;
Prime : constant Prime_List := Get_Primes;
Count : Natural := 0;
begin
Put_Line ("Additive primes <500:");
for N in Prime'Range loop
if Prime (N) and then Prime (Sum_Of (N)) then
Count := Count + 1;
Put (N, Width => 5);
if Count mod Columns = 0 then
New_Line;
end if;
end if;
end loop;
New_Line;
Put ("There are ");
Put (Count, Width => 2);
Put (" additive primes.");
New_Line;
end Additive_Primes;

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on sieveOfEratosthenes(limit)
script o
property numberList : {missing value}
end script
repeat with n from 2 to limit
set end of o's numberList to n
end repeat
repeat with n from 2 to (limit ^ 0.5) div 1
if (item n of o's numberList is n) then
repeat with multiple from n * n to limit by n
set item multiple of o's numberList to missing value
end repeat
end if
end repeat
return o's numberList's numbers
end sieveOfEratosthenes
on sumOfDigits(n) -- n assumed to be a positive decimal integer.
set sum to n mod 10
set n to n div 10
repeat until (n = 0)
set sum to sum + n mod 10
set n to n div 10
end repeat
return sum
end sumOfDigits
on additivePrimes(limit)
script o
property primes : sieveOfEratosthenes(limit)
property additives : {}
end script
repeat with p in o's primes
if (sumOfDigits(p) is in o's primes) then set end of o's additives to p's contents
end repeat
return o's additives
end additivePrimes
-- Task code:
tell additivePrimes(499) to return {|additivePrimes<500|:it, numberThereof:count}

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{|additivePrimes<500|:{2, 3, 5, 7, 11, 23, 29, 41, 43, 47, 61, 67, 83, 89, 101, 113, 131, 137, 139, 151, 157, 173, 179, 191, 193, 197, 199, 223, 227, 229, 241, 263, 269, 281, 283, 311, 313, 317, 331, 337, 353, 359, 373, 379, 397, 401, 409, 421, 443, 449, 461, 463, 467, 487}, numberThereof:54}

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0 E = 500
1 F = E - 1:L = LEN ( STR$ (F)) + 1: FOR I = 2 TO L:S$ = S$ + CHR$ (32): NEXT I: DIM P(E):P(0) = - 1:P(1) = - 1: FOR I = 2 TO SQR (F): IF NOT P(I) THEN FOR J = I * 2 TO E STEP I:P(J) = - 1: NEXT J
2 NEXT I: FOR I = B TO F: IF NOT P(I) THEN GOSUB 4
3 NEXT I: PRINT : PRINT N" ADDITIVE PRIMES FOUND BELOW "E;: END
4 S = 0: IF I THEN FOR J = I TO 0 STEP 0:J1 = INT (J / 10):S = S + (J - J1 * 10):J = J1: NEXT J
5 IF NOT P(S) THEN N = N + 1: PRINT RIGHT$ (S$ + STR$ (I),L);
6 RETURN

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additives: select 2..500 'x -> and? prime? x prime? sum digits x
loop split.every:10 additives 'a ->
print map a => [pad to :string & 4]
print ["\nFound" size additives "additive primes up to 500"]

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10 DEFINT A-Z: E=500
20 DIM P(E): P(0)=-1: P(1)=-1
30 FOR I=2 TO SQR(E)
40 IF NOT P(I) THEN FOR J=I*2 TO E STEP I: P(J)=-1: NEXT
50 NEXT
60 FOR I=B TO E: IF P(I) GOTO 100
70 J=I: S=0
80 IF J>0 THEN S=S+J MOD 10: J=J\10: GOTO 80
90 IF NOT P(S) THEN N=N+1: PRINT I,
100 NEXT
110 PRINT: PRINT N;" additive primes found below ";E

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print "Prime", "Digit Sum"
for i = 2 to 499
if isprime(i) then
s = digSum(i)
if isPrime(s) then print i, s
end if
next i
end
function isPrime(v)
if v < 2 then return False
if v mod 2 = 0 then return v = 2
if v mod 3 = 0 then return v = 3
d = 5
while d * d <= v
if v mod d = 0 then return False else d += 2
end while
return True
end function
function digsum(n)
s = 0
while n
s += n mod 10
n /= 10
end while
return s
end function

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get "libhdr"
manifest $( limit = 500 $)
let dsum(n) =
n=0 -> 0,
dsum(n/10) + n rem 10
let sieve(prime, n) be
$( 0!prime := false
1!prime := false
for i=2 to n do i!prime := true
for i=2 to n/2
if i!prime
$( let j=i+i
while j<=n
$( j!prime := false
j := j+i
$)
$)
$)
let additive(prime, n) = n!prime & dsum(n)!prime
let start() be
$( let prime = vec limit
let num = 0
sieve(prime, limit)
for i=2 to limit
if additive(prime,i)
$( writed(i,5)
num := num + 1
if num rem 10 = 0 then wrch('*N')
$)
writef("*N*NFound %N additive primes < %N.*N", num, limit)
$)

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#include <iomanip>
#include <iostream>
bool is_prime(unsigned int n) {
if (n < 2)
return false;
if (n % 2 == 0)
return n == 2;
if (n % 3 == 0)
return n == 3;
for (unsigned int p = 5; p * p <= n; p += 4) {
if (n % p == 0)
return false;
p += 2;
if (n % p == 0)
return false;
}
return true;
}
unsigned int digit_sum(unsigned int n) {
unsigned int sum = 0;
for (; n > 0; n /= 10)
sum += n % 10;
return sum;
}
int main() {
const unsigned int limit = 500;
std::cout << "Additive primes less than " << limit << ":\n";
unsigned int count = 0;
for (unsigned int n = 1; n < limit; ++n) {
if (is_prime(digit_sum(n)) && is_prime(n)) {
std::cout << std::setw(3) << n;
if (++count % 10 == 0)
std::cout << '\n';
else
std::cout << ' ';
}
}
std::cout << '\n' << count << " additive primes found.\n";
}

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#include <stdbool.h>
#include <stdio.h>
#include <string.h>
void memoizeIsPrime( bool * result, const int N )
{
result[2] = true;
result[3] = true;
int prime[N];
prime[0] = 3;
int end = 1;
for (int n = 5; n < N; n += 2)
{
bool n_is_prime = true;
for (int i = 0; i < end; ++i)
{
const int PRIME = prime[i];
if (n % PRIME == 0)
{
n_is_prime = false;
break;
}
if (PRIME * PRIME > n)
{
break;
}
}
if (n_is_prime)
{
prime[end++] = n;
result[n] = true;
}
}
}/* memoizeIsPrime */
int sumOfDecimalDigits( int n )
{
int sum = 0;
while (n > 0)
{
sum += n % 10;
n /= 10;
}
return sum;
}/* sumOfDecimalDigits */
int main( void )
{
const int N = 500;
printf( "Rosetta Code: additive primes less than %d:\n", N );
bool is_prime[N];
memset( is_prime, 0, sizeof(is_prime) );
memoizeIsPrime( is_prime, N );
printf( " 2" );
int count = 1;
for (int i = 3; i < N; i += 2)
{
if (is_prime[i] && is_prime[sumOfDecimalDigits( i )])
{
printf( "%4d", i );
++count;
if ((count % 10) == 0)
{
printf( "\n" );
}
}
}
printf( "\nThose were %d additive primes.\n", count );
return 0;
}/* main */

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% Sieve of Erastothenes
% Returns an array [1..max] marking the primes
sieve = proc (max: int) returns (array[bool])
prime: array[bool] := array[bool]$fill(1, max, true)
prime[1] := false
for p: int in int$from_to(2, max/2) do
if prime[p] then
for comp: int in int$from_to_by(p*2, max, p) do
prime[comp] := false
end
end
end
return(prime)
end sieve
% Sum the digits of a number
digit_sum = proc (n: int) returns (int)
sum: int := 0
while n ~= 0 do
sum := sum + n // 10
n := n / 10
end
return(sum)
end digit_sum
start_up = proc ()
max = 500
po: stream := stream$primary_output()
count: int := 0
prime: array[bool] := sieve(max)
for i: int in array[bool]$indexes(prime) do
if prime[i] cand prime[digit_sum(i)] then
count := count + 1
stream$putright(po, int$unparse(i), 5)
if count//10 = 0 then stream$putl(po, "") end
end
end
stream$putl(po, "\nFound " || int$unparse(count) ||
" additive primes < " || int$unparse(max))
end start_up

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IDENTIFICATION DIVISION.
PROGRAM-ID. ADDITIVE-PRIMES.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 VARIABLES.
03 MAXIMUM PIC 999.
03 AMOUNT PIC 999.
03 CANDIDATE PIC 999.
03 DIGIT PIC 9 OCCURS 3 TIMES,
REDEFINES CANDIDATE.
03 DIGITSUM PIC 99.
01 PRIME-DATA.
03 COMPOSITE-FLAG PIC X OCCURS 500 TIMES.
88 PRIME VALUE ' '.
03 SIEVE-PRIME PIC 999.
03 SIEVE-COMP-START PIC 999.
03 SIEVE-COMP PIC 999.
03 SIEVE-MAX PIC 999.
01 OUT-FMT.
03 NUM-FMT PIC ZZZ9.
03 OUT-LINE PIC X(40).
03 OUT-PTR PIC 99.
PROCEDURE DIVISION.
BEGIN.
MOVE 500 TO MAXIMUM.
MOVE 1 TO OUT-PTR.
PERFORM SIEVE.
MOVE ZERO TO AMOUNT.
PERFORM TEST-NUMBER
VARYING CANDIDATE FROM 2 BY 1
UNTIL CANDIDATE IS GREATER THAN MAXIMUM.
DISPLAY OUT-LINE.
DISPLAY SPACES.
MOVE AMOUNT TO NUM-FMT.
DISPLAY 'Amount of additive primes found: ' NUM-FMT.
STOP RUN.
TEST-NUMBER.
ADD DIGIT(1), DIGIT(2), DIGIT(3) GIVING DIGITSUM.
IF PRIME(CANDIDATE) AND PRIME(DIGITSUM),
ADD 1 TO AMOUNT,
PERFORM WRITE-NUMBER.
WRITE-NUMBER.
MOVE CANDIDATE TO NUM-FMT.
STRING NUM-FMT DELIMITED BY SIZE INTO OUT-LINE
WITH POINTER OUT-PTR.
IF OUT-PTR IS GREATER THAN 40,
DISPLAY OUT-LINE,
MOVE SPACES TO OUT-LINE,
MOVE 1 TO OUT-PTR.
SIEVE.
MOVE SPACES TO PRIME-DATA.
DIVIDE MAXIMUM BY 2 GIVING SIEVE-MAX.
PERFORM SIEVE-OUTER-LOOP
VARYING SIEVE-PRIME FROM 2 BY 1
UNTIL SIEVE-PRIME IS GREATER THAN SIEVE-MAX.
SIEVE-OUTER-LOOP.
IF PRIME(SIEVE-PRIME),
MULTIPLY SIEVE-PRIME BY 2 GIVING SIEVE-COMP-START,
PERFORM SIEVE-INNER-LOOP
VARYING SIEVE-COMP
FROM SIEVE-COMP-START BY SIEVE-PRIME
UNTIL SIEVE-COMP IS GREATER THAN MAXIMUM.
SIEVE-INNER-LOOP.
MOVE 'X' TO COMPOSITE-FLAG(SIEVE-COMP).

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(defun sum-of-digits (n)
"Return the sum of the digits of a number"
(do* ((sum 0 (+ sum rem))
rem )
((zerop n) sum)
(multiple-value-setq (n rem) (floor n 10)) ))
(defun additive-primep (n)
(and (primep n) (primep (sum-of-digits n))) )
; To test if a number is prime we can use a number of different methods. Here I use Wilson's Theorem (see Primality by Wilson's theorem):
(defun primep (n)
(unless (zerop n)
(zerop (mod (1+ (factorial (1- n))) n)) ))
(defun factorial (n)
(if (< n 2) 1 (* n (factorial (1- n)))) )

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# Fast/simple way to generate primes for small values.
# Uses P3 Prime Generator (PG) and its Prime Generator Sequence (PGS).
def prime?(n) # P3 Prime Generator primality test
return false unless (n | 1 == 3 if n < 5) || (n % 6) | 4 == 5
sqrt_n = Math.isqrt(n) # For Crystal < 1.2.0 use Math.sqrt(n).to_i
pc = typeof(n).new(5)
while pc <= sqrt_n
return false if n % pc == 0 || n % (pc + 2) == 0
pc += 6
end
true
end
def additive_primes(n)
primes = [2, 3]
pc, inc = 5, 2
while pc < n
primes << pc if prime?(pc) && prime?(pc.digits.sum)
pc += inc; inc ^= 0b110 # generate P3 sequence: 5 7 11 13 17 19 ...
end
primes # list of additive primes <= n
end
nn = 500
addprimes = additive_primes(nn)
maxdigits = addprimes.last.digits.size
addprimes.each_with_index { |n, idx| printf "%*d ", maxdigits, n; print "\n" if idx % 10 == 9 } # more efficient
#addprimes.each_with_index { |n, idx| print "%#{maxdigits}d " % n; print "\n" if idx % 10 == 9} # alternatively
puts "\n#{addprimes.size} additive primes below #{nn}."
puts
nn = 5000
addprimes = additive_primes(nn)
maxdigits = addprimes.last.digits.size
addprimes.each_with_index { |n, idx| printf "%*d ", maxdigits, n; print "\n" if idx % 10 == 9 } # more efficient
puts "\n#{addprimes.size} additive primes below #{nn}."

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@ -0,0 +1,29 @@
import 'dart:math';
void main() {
const limit = 500;
print('Additive primes less than $limit :');
int count = 0;
for (int n = 1; n < limit; ++n) {
if (isPrime(digit_sum(n)) && isPrime(n)) {
print(' $n');
++count;
}
}
print('$count additive primes found.');
}
bool isPrime(int n) {
if (n <= 1) return false;
if (n == 2) return true;
for (int i = 2; i <= sqrt(n); ++i) {
if (n % i == 0) return false;
}
return true;
}
int digit_sum(int n) {
int sum = 0;
for (int m = n; m > 0; m ~/= 10) sum += m % 10;
return sum;
}

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{These routines would normally be in libraries but are shown here for clarity}
function IsPrime(N: int64): boolean;
{Fast, optimised prime test}
var I,Stop: int64;
begin
if (N = 2) or (N=3) then Result:=true
else if (n <= 1) or ((n mod 2) = 0) or ((n mod 3) = 0) then Result:= false
else
begin
I:=5;
Stop:=Trunc(sqrt(N+0.0));
Result:=False;
while I<=Stop do
begin
if ((N mod I) = 0) or ((N mod (I + 2)) = 0) then exit;
Inc(I,6);
end;
Result:=True;
end;
end;
function SumDigits(N: integer): integer;
{Sum the integers in a number}
var T: integer;
begin
Result:=0;
repeat
begin
T:=N mod 10;
N:=N div 10;
Result:=Result+T;
end
until N<1;
end;
procedure ShowDigitSumPrime(Memo: TMemo);
var N,Sum,Cnt: integer;
var NS,S: string;
begin
Cnt:=0;
S:='';
for N:=1 to 500-1 do
if IsPrime(N) then
begin
Sum:=SumDigits(N);
if IsPrime(Sum) then
begin
Inc(Cnt);
S:=S+Format('%6d',[N]);
if (Cnt mod 8)=0 then S:=S+CRLF;
end;
end;
Memo.Lines.Add(S);
Memo.Lines.Add('Count = '+IntToStr(Cnt));
end;

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@ -0,0 +1,40 @@
proc sieve([*] bool prime) void:
word max, p, c;
max := dim(prime,1)-1;
prime[0] := false;
prime[1] := false;
for p from 2 upto max do prime[p] := true od;
for p from 2 upto max/2 do
for c from p*2 by p upto max do
prime[c] := false
od
od
corp
proc digit_sum(word num) byte:
byte sum;
sum := 0;
while
sum := sum + num % 10;
num := num / 10;
num /= 0
do od;
sum
corp
proc main() void:
word MAX = 500;
word p, n;
[MAX]bool prime;
sieve(prime);
n := 0;
for p from 2 upto MAX-1 do
if prime[p] and prime[digit_sum(p)] then
write(p:4);
n := n + 1;
if n % 20 = 0 then writeln() fi
fi
od;
writeln();
writeln("There are ", n, " additive primes below ", MAX)
corp

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@ -0,0 +1,27 @@
proc isprime x . r .
r = 1
for i = 2 to sqrt x
if x mod i = 0
r = 0
break 2
.
.
.
proc digsum n . sum .
sum = 0
while n > 0
sum += n mod 10
n = n div 10
.
.
for i = 2 to 500
call isprime i r
if r = 1
call digsum i s
call isprime s r
if r = 1
write i & " "
.
.
.
print ""

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@ -0,0 +1,16 @@
main(_) ->
AddPrimes = [N || N <- lists:seq(2,500), isprime(N) andalso isprime(digitsum(N))],
io:format("The additive primes up to 500 are:~n~p~n~n", [AddPrimes]),
io:format("There are ~b of them.~n", [length(AddPrimes)]).
isprime(N) when N < 2 -> false;
isprime(N) -> isprime(N, 2, 0, <<1, 2, 2, 4, 2, 4, 2, 4, 6, 2, 6>>).
isprime(N, D, J, Wheel) when J =:= byte_size(Wheel) -> isprime(N, D, 3, Wheel);
isprime(N, D, _, _) when D*D > N -> true;
isprime(N, D, _, _) when N rem D =:= 0 -> false;
isprime(N, D, J, Wheel) -> isprime(N, D + binary:at(Wheel, J), J + 1, Wheel).
digitsum(N) -> digitsum(N, 0).
digitsum(0, S) -> S;
digitsum(N, S) -> digitsum(N div 10, S + N rem 10).

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@ -0,0 +1,3 @@
// Additive Primes. Nigel Galloway: March 22nd., 2021
let rec fN g=function n when n<10->n+g |n->fN(g+n%10)(n/10)
primes32()|>Seq.takeWhile((>)500)|>Seq.filter(fN 0>>isPrime)|>Seq.iter(printf "%d "); printfn ""

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@ -0,0 +1,9 @@
USING: formatting grouping io kernel math math.primes
prettyprint sequences ;
: sum-digits ( n -- sum )
0 swap [ 10 /mod rot + swap ] until-zero ;
499 primes-upto [ sum-digits prime? ] filter
[ 9 group simple-table. nl ]
[ length "Found %d additive primes < 500.\n" printf ] bi

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@ -0,0 +1,18 @@
Function Digsum(n) =
digsum := 0;
while n>0 do
digsum := digsum + n|10;
n:=n\10;
od;
digsum.;
nadd := 0;
!!'Additive primes below 500 are';
for p=1 to 500 do
if Isprime(p) and Isprime(Digsum(p)) then
!!(p,' -> ',Digsum(p));
nadd := nadd+1;
fi od;
!!('There were ',nadd);

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@ -0,0 +1,40 @@
: prime? ( n -- ? ) here + c@ 0= ;
: notprime! ( n -- ) here + 1 swap c! ;
: prime_sieve ( n -- )
here over erase
0 notprime!
1 notprime!
2
begin
2dup dup * >
while
dup prime? if
2dup dup * do
i notprime!
dup +loop
then
1+
repeat
2drop ;
: digit_sum ( u -- u )
dup 10 < if exit then
10 /mod recurse + ;
: print_additive_primes ( n -- )
." Additive primes less than " dup 1 .r ." :" cr
dup prime_sieve
0 swap
1 do
i prime? if
i digit_sum prime? if
i 3 .r
1+ dup 10 mod 0= if cr else space then
then
then
loop
cr . ." additive primes found." cr ;
500 print_additive_primes
bye

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Program AdditivePrimes;
Const max_number = 500;
Var is_prime : array Of Boolean;
Procedure sieve(Var arr: Array Of boolean );
{use Sieve of Eratosthenes to find all primes to max number}
Var i,j : NativeUInt;
Begin
For i := 2 To high(arr) Do
arr[i] := True; // set all bits to be True
For i := 2 To high(arr) Do
Begin
If (arr[i]) Then
For j := 2 To (high(arr) Div i) Do
arr[i * j] := False;
End;
End;
Function GetSumOfDigits(num: NativeUInt): longint;
{calcualte the sum of digits of a number}
Var
sum : longint = 0;
dummy: NativeUInt;
Begin
Repeat
dummy := num;
num := num Div 10;
Inc(sum, dummy - (num SHL 3 + num SHL 1));
Until num < 1;
GetSumOfDigits := sum;
End;
Var x : NativeUInt = 2; {first prime}
counter : longint = 0;
Begin
setlength(is_prime,max_number); //set length of array to max_number
Sieve(is_prime); //apply Sieve
{since 2 is the only even prime, let's do it separate}
If is_prime[x] And is_prime[GetSumOfDigits(x)] Then
Begin
write(x:4);
inc(counter);
End;
inc(x);
While x < max_number Do
Begin
If is_prime[x] And is_prime[GetSumOfDigits(x)] Then
Begin
if counter mod 10 = 0 then writeln();
write(x:4);
inc(counter);
End;
inc(x,2);
End;
writeln();
writeln();
writeln(counter,' additive primes found.');
End.

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#include "isprime.bas"
function digsum( n as uinteger ) as uinteger
dim as uinteger s
while n
s+=n mod 10
n\=10
wend
return s
end function
dim as uinteger s
print "Prime","Digit Sum"
for i as uinteger = 2 to 499
if isprime(i) then
s = digsum(i)
if isprime(s) then
print i, s
end if
end if
next i

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@ -0,0 +1,3 @@
vals = toArray[select[primes[2, 500], {|x| isPrime[sum[integerDigits[x]]]}]]
println[formatTable[columnize[vals, 10]]]
println["\n" + length[vals] + " values found."]

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@ -0,0 +1,37 @@
local fn IsPrime( n as NSUInteger ) as BOOL
NSUInteger i
BOOL result = YES
if ( n < 2 ) then exit fn = NO
for i = 2 to n + 1
if ( i * i <= n ) and ( n mod i == 0 )
exit fn = NO
end if
next
end fn = result
local fn DigSum( n as NSUInteger ) as NSUInteger
NSUInteger s = 0
while ( n > 0 )
s += ( n mod 10 )
n /= 10
wend
end fn = s
void local fn AdditivePrimes( n as NSUInteger )
NSUInteger i, s = 0, counter = 0
printf @"Additive Primes:"
for i = 2 to n
if ( fn IsPrime(i) ) and ( fn IsPrime( fn DigSum(i) ) )
s++
printf @"%4ld \b", i : counter++
if counter == 10 then counter = 0 : print
end if
next
printf @"\n\nFound %lu additive primes less than %lu.", s, n
end fn
fn AdditivePrimes( 500 )
HandleEvents

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@ -0,0 +1,60 @@
package main
import "fmt"
func isPrime(n int) bool {
switch {
case n < 2:
return false
case n%2 == 0:
return n == 2
case n%3 == 0:
return n == 3
default:
d := 5
for d*d <= n {
if n%d == 0 {
return false
}
d += 2
if n%d == 0 {
return false
}
d += 4
}
return true
}
}
func sumDigits(n int) int {
sum := 0
for n > 0 {
sum += n % 10
n /= 10
}
return sum
}
func main() {
fmt.Println("Additive primes less than 500:")
i := 2
count := 0
for {
if isPrime(i) && isPrime(sumDigits(i)) {
count++
fmt.Printf("%3d ", i)
if count%10 == 0 {
fmt.Println()
}
}
if i > 2 {
i += 2
} else {
i++
}
if i > 499 {
break
}
}
fmt.Printf("\n\n%d additive primes found.\n", count)
}

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@ -0,0 +1,17 @@
import Data.List (unfoldr)
-- infinite list of primes
primes = 2 : sieve [3,5..]
where sieve (x:xs) = x : sieve (filter (\y -> y `mod` x /= 0) xs)
-- primarity test, effective for numbers less then billion
isPrime n = all (\p -> n `mod` p /= 0) $ takeWhile (< sqrtN) primes
where sqrtN = round . sqrt . fromIntegral $ n
-- decimal digits of a number
digits = unfoldr f
where f 0 = Nothing
f n = let (q, r) = divMod n 10 in Just (r,q)
-- test for an additive prime
isAdditivePrime n = isPrime n && (isPrime . sum . digits) n

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@ -0,0 +1,2 @@
(#~ 1 p: [:+/@|: 10&#.inv) i.&.(p:inv) 500
2 3 5 7 11 23 29 41 43 47 61 67 83 89 101 113 131 137 139 151 157 173 179 191 193 197 199 223 227 229 241 263 269 281 283 311 313 317 331 337 353 359 373 379 397 401 409 421 443 449 461 463 467 487

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@ -0,0 +1,37 @@
public class additivePrimes {
public static void main(String[] args) {
int additive_primes = 0;
for (int i = 2; i < 500; i++) {
if(isPrime(i) && isPrime(digitSum(i))){
additive_primes++;
System.out.print(i + " ");
}
}
System.out.print("\nFound " + additive_primes + " additive primes less than 500");
}
static boolean isPrime(int n) {
int counter = 1;
if (n < 2 || (n != 2 && n % 2 == 0) || (n != 3 && n % 3 == 0)) {
return false;
}
while (counter * 6 - 1 <= Math.sqrt(n)) {
if (n % (counter * 6 - 1) == 0 || n % (counter * 6 + 1) == 0) {
return false;
} else {
counter++;
}
}
return true;
}
static int digitSum(int n) {
int sum = 0;
while (n > 0) {
sum += n % 10;
n /= 10;
}
return sum;
}
}

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@ -0,0 +1,32 @@
def is_prime:
. as $n
| if ($n < 2) then false
elif ($n % 2 == 0) then $n == 2
elif ($n % 3 == 0) then $n == 3
elif ($n % 5 == 0) then $n == 5
elif ($n % 7 == 0) then $n == 7
elif ($n % 11 == 0) then $n == 11
elif ($n % 13 == 0) then $n == 13
elif ($n % 17 == 0) then $n == 17
elif ($n % 19 == 0) then $n == 19
else {i:23}
| until( (.i * .i) > $n or ($n % .i == 0); .i += 2)
| .i * .i > $n
end;
# Emit an array of primes less than `.`
def primes:
if . < 2 then []
else [2] + [range(3; .; 2) | select(is_prime)]
end;
def add(s): reduce s as $x (null; . + $x);
def sumdigits: add(tostring | explode[] | [.] | implode | tonumber);
# Pretty-printing
def nwise($n):
def n: if length <= $n then . else .[0:$n] , (.[$n:] | n) end;
n;
def lpad($len): tostring | ($len - length) as $l | (" " * $l)[:$l] + .;

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@ -0,0 +1,16 @@
# Input: a number n
# Output: an array of additive primes less than n
def additive_primes:
primes
| . as $primes
| reduce .[] as $p (null;
( $p | sumdigits ) as $sum
| if (($primes | bsearch($sum)) > -1)
then . + [$p]
else .
end );
"Erdős primes under 500:",
(500 | additive_primes
| ((nwise(10) | map(lpad(4)) | join(" ")),
"\n\(length) additive primes found."))

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@ -0,0 +1,14 @@
using Primes
let
p = primesmask(500)
println("Additive primes under 500:")
pcount = 0
for i in 2:499
if p[i] && p[sum(digits(i))]
pcount += 1
print(lpad(i, 4), pcount % 20 == 0 ? "\n" : "")
end
end
println("\n\n$pcount additive primes found.")
end

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@ -0,0 +1,31 @@
fun isPrime(n: Int): Boolean {
if (n <= 3) return n > 1
if (n % 2 == 0 || n % 3 == 0) return false
var i = 5
while (i * i <= n) {
if (n % i == 0 || n % (i + 2) == 0) return false
i += 6
}
return true
}
fun digitSum(n: Int): Int {
var sum = 0
var num = n
while (num > 0) {
sum += num % 10
num /= 10
}
return sum
}
fun main() {
var additivePrimes = 0
for (i in 2 until 500) {
if (isPrime(i) and isPrime(digitSum(i))) {
additivePrimes++
print("$i ")
}
}
println("\nFound $additivePrimes additive primes less than 500")
}

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@ -0,0 +1,47 @@
#!/bin/ksh
# Prime numbers for which the sum of their decimal digits are also primes
# # Variables:
#
integer MAX_n=500
# # Functions:
#
# # Function _isprime(n) return 1 for prime, 0 for not prime
#
function _isprime {
typeset _n ; integer _n=$1
typeset _i ; integer _i
(( _n < 2 )) && return 0
for (( _i=2 ; _i*_i<=_n ; _i++ )); do
(( ! ( _n % _i ) )) && return 0
done
return 1
}
# # Function _sumdigits(n) return sum of n's digits
#
function _sumdigits {
typeset _n ; _n=$1
typeset _i _sum ; integer _i _sum=0
for ((_i=0; _i<${#_n}; _i++)); do
(( _sum+=${_n:${_i}:1} ))
done
echo ${_sum}
}
######
# main #
######
integer i digsum
for ((i=2; i<MAX_n; i++)); do
_isprime ${i} && (( ! $? )) && continue
digsum=$(_sumdigits ${i})
_isprime ${digsum} ; (( $? )) && printf "%4d " ${i}
done
print

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@ -0,0 +1,40 @@
{def isprime
{def isprime.loop
{lambda {:n :m :i}
{if {> :i :m}
then true
else {if {= {% :n :i} 0}
then false
else {isprime.loop :n :m {+ :i 2}}
}}}}
{lambda {:n}
{if {or {= :n 2} {= :n 3} {= :n 5} {= :n 7}}
then true
else {if {or {< : n 2} {= {% :n 2} 0}}
then false
else {isprime.loop :n {sqrt :n} 3}
}}}}
-> isprime
{def digit.sum
{def digit.sum.loop
{lambda {:n :sum}
{if {> :n 0}
then {digit.sum.loop {floor {/ :n 10}}
{+ :sum {% :n 10}}}
else :sum}}}
{lambda {:n}
{digit.sum.loop :n 0}}}
-> digit.sum
{S.replace \s by space in
{S.map {lambda {:i}
{if {and {isprime :i}
{isprime {digit.sum :i}}}
then :i
else}}
{S.serie 2 500}}}
->
2 3 5 7 11 23 29 41 43 47 61 67 83 89 101 113 131 137 139 151 157 173 179 191 193 197 199 223 227 229 241 263 269 281 283 311 313 317 331 337 353 359 373 379 397 401 409 421 443 449 461 463 467 487
i.e 54 additive primes until 500.

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@ -0,0 +1,17 @@
val .isPrime = f .i == 2 or .i > 2 and not any f(.x) .i div .x, pseries 2 .. .i ^/ 2
val .sumDigits = f fold f{+}, s2n toString .i
writeln "Additive primes less than 500:"
var .count = 0
for .i in [2] ~ series(3..500, 2) {
if .isPrime(.i) and .isPrime(.sumDigits(.i)) {
write $"\.i:3; "
.count += 1
if .count div 10: writeln()
}
}
writeln $"\n\n\.count; additive primes found.\n"

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@ -0,0 +1,13 @@
function sumdigits(n)
local sum = 0
while n > 0 do
sum = sum + n % 10
n = math.floor(n/10)
end
return sum
end
primegen:generate(nil, 500)
aprimes = primegen:filter(function(n) return primegen.tbd(sumdigits(n)) end)
print(table.concat(aprimes, " "))
print("Count:", #aprimes)

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@ -0,0 +1,3 @@
ClearAll[AdditivePrimeQ]
AdditivePrimeQ[n_Integer] := PrimeQ[n] \[And] PrimeQ[Total[IntegerDigits[n]]]
Select[Range[500], AdditivePrimeQ]

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@ -0,0 +1,54 @@
MODULE AdditivePrimes;
FROM InOut IMPORT WriteString, WriteCard, WriteLn;
CONST
Max = 500;
VAR
N: CARDINAL;
Count: CARDINAL;
Prime: ARRAY [2..Max] OF BOOLEAN;
PROCEDURE DigitSum(n: CARDINAL): CARDINAL;
BEGIN
IF n < 10 THEN
RETURN n;
ELSE
RETURN (n MOD 10) + DigitSum(n DIV 10);
END;
END DigitSum;
PROCEDURE Sieve;
VAR i, j, max2: CARDINAL;
BEGIN
FOR i := 2 TO Max DO
Prime[i] := TRUE;
END;
FOR i := 2 TO Max DIV 2 DO
IF Prime[i] THEN;
j := i*2;
WHILE j <= Max DO
Prime[j] := FALSE;
j := j + i;
END;
END;
END;
END Sieve;
BEGIN
Count := 0;
Sieve();
FOR N := 2 TO Max DO
IF Prime[N] AND Prime[DigitSum(N)] THEN
WriteCard(N, 4);
Count := Count + 1;
IF Count MOD 10 = 0 THEN WriteLn(); END;
END;
END;
WriteLn();
WriteString('There are '); WriteCard(Count,0);
WriteString(' additive primes less than '); WriteCard(Max,0);
WriteString('.');
WriteLn();
END AdditivePrimes.

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@ -0,0 +1,31 @@
import math, strutils
const N = 499
# Sieve of Erathostenes.
var composite: array[2..N, bool] # Initialized to false, ie. prime.
for n in 2..sqrt(N.toFloat).int:
if not composite[n]:
for k in countup(n * n, N, n):
composite[k] = true
func digitSum(n: Positive): Natural =
## Compute sum of digits.
var n = n.int
while n != 0:
result += n mod 10
n = n div 10
echo "Additive primes less than 500:"
var count = 0
for n in 2..N:
if not composite[n] and not composite[digitSum(n)]:
inc count
stdout.write ($n).align(3)
stdout.write if count mod 10 == 0: '\n' else: ' '
echo()
echo "\nNumber of additive primes found: ", count

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@ -0,0 +1,14 @@
let rec digit_sum n =
if n < 10 then n else n mod 10 + digit_sum (n / 10)
let is_prime n =
let rec test x =
let q = n / x in x > q || x * q <> n && n mod (x + 2) <> 0 && test (x + 6)
in if n < 5 then n lor 1 = 3 else n land 1 <> 0 && n mod 3 <> 0 && test 5
let is_additive_prime n =
is_prime n && is_prime (digit_sum n)
let () =
Seq.ints 0 |> Seq.take_while ((>) 500) |> Seq.filter is_additive_prime
|> Seq.iter (Printf.printf " %u") |> print_newline

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@ -0,0 +1,8 @@
hasPrimeDigitsum(n)=isprime(sumdigits(n)); \\ see A028834 in the OEIS
v1 = select(isprime, select(hasPrimeDigitsum, [1..499]));
v2 = select(hasPrimeDigitsum, select(isprime, [1..499]));
v3 = select(hasPrimeDigitsum, primes([1, 499]));
s=0; forprime(p=2,499, if(hasPrimeDigitsum(p), s++)); s;
[#v1, #v2, #v3, s]

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@ -0,0 +1,43 @@
C :z=2
:c=0
:max=500
*number
C :n=z
U :*digsum
C :n=s
U :*prime
J (p=0):*next
C :n=z
U :*prime
J (p=0):*next
T :#z
C :c=c+1
*next
C :z=z+1
J (z<max):*number
T :There are #c additive primes below #max
E :
*prime
C :p=1
E (n<4):
C :p=0
E (n=2*(n/2)):
C :i=3
:m=n/2
*ptest
E (n=i*(n/i)):
C :i=i+2
J (i<=m):*ptest
C :p=1
E :
*digsum
C :s=0
:i=n
*digit
C :j=i/10
:s=s+(i-j*10)
:i=j
J (i>0):*digit
E :

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@ -0,0 +1,148 @@
program AdditivePrimes;
{$IFDEF FPC}
{$MODE DELPHI}{$CODEALIGN proc=16}
{$ELSE}
{$APPTYPE CONSOLE}
{$ENDIF}
{$DEFINE DO_OUTPUT}
uses
sysutils;
const
RANGE = 500; // 1000*1000;//
MAX_OFFSET = 0; // 1000*1000*1000;//
type
tNum = array [0 .. 15] of byte;
tNumSum = record
dgtNum, dgtSum: tNum;
dgtLen, num: Uint32;
end;
tpNumSum = ^tNumSum;
function isPrime(n: Uint32): boolean;
const
wheeldiff: array [0 .. 7] of Uint32 = (+6, +4, +2, +4, +2, +4, +6, +2);
var
p: NativeUInt;
flipflop: Int32;
begin
if n < 64 then
EXIT(n in [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47,
53, 59, 61])
else
begin
IF (n AND 1 = 0) OR (n mod 3 = 0) OR (n mod 5 = 0) then
EXIT(false);
result := true;
p := 1;
flipflop := 6;
while result do
Begin
p := p + wheeldiff[flipflop];
if p * p > n then
BREAK;
result := n mod p <> 0;
flipflop := flipflop - 1;
if flipflop < 0 then
flipflop := 7;
end
end
end;
procedure IncNum(var NumSum: tNumSum; delta: Uint32);
const
BASE = 10;
var
carry, dg: Uint32;
le: Int32;
Begin
if delta = 0 then
EXIT;
le := 0;
with NumSum do
begin
num := num + delta;
repeat
carry := delta div BASE;
delta := delta - BASE * carry;
dg := dgtNum[le] + delta;
IF dg >= BASE then
Begin
dg := dg - BASE;
inc(carry);
end;
dgtNum[le] := dg;
inc(le);
delta := carry;
until carry = 0;
if dgtLen < le then
dgtLen := le;
// correct sum of digits // le is >= 1
delta := dgtSum[le];
repeat
dec(le);
delta := delta + dgtNum[le];
dgtSum[le] := delta;
until le = 0;
end;
end;
var
NumSum: tNumSum;
s: AnsiString;
i, k, cnt, Nr: NativeUInt;
ColWidth, MAXCOLUMNS, NextRowCnt: NativeUInt;
BEGIN
ColWidth := Trunc(ln(MAX_OFFSET + RANGE) / ln(10)) + 2;
MAXCOLUMNS := 80;
NextRowCnt := MAXCOLUMNS DIV ColWidth;
fillchar(NumSum, SizeOf(NumSum), #0);
NumSum.dgtLen := 1;
IncNum(NumSum, MAX_OFFSET);
setlength(s, ColWidth);
fillchar(s[1], ColWidth, ' ');
// init string
with NumSum do
Begin
For i := dgtLen - 1 downto 0 do
s[ColWidth - i] := AnsiChar(dgtNum[i] + 48);
// reset digits lenght to get the max changed digits since last update of string
dgtLen := 0;
end;
cnt := 0;
Nr := NextRowCnt;
For i := 0 to RANGE do
with NumSum do
begin
if isPrime(dgtSum[0]) then
if isPrime(num) then
Begin
cnt := cnt + 1;
dec(Nr);
// correct changed digits in string s
For k := dgtLen - 1 downto 0 do
s[ColWidth - k] := AnsiChar(dgtNum[k] + 48);
dgtLen := 0;
{$IFDEF DO_OUTPUT}
write(s);
if Nr = 0 then
begin
writeln;
Nr := NextRowCnt;
end;
{$ENDIF}
end;
IncNum(NumSum, 1);
end;
if Nr <> NextRowCnt then
write(#10);
writeln(cnt, ' additive primes found.');
END.

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@ -0,0 +1,15 @@
use strict;
use warnings;
use ntheory 'is_prime';
use List::Util <sum max>;
sub pp {
my $format = ('%' . (my $cw = 1+length max @_) . 'd') x @_;
my $width = ".{@{[$cw * int 60/$cw]}}";
(sprintf($format, @_)) =~ s/($width)/$1\n/gr;
}
my($limit, @ap) = 500;
is_prime($_) and is_prime(sum(split '',$_)) and push @ap, $_ for 1..$limit;
print @ap . " additive primes < $limit:\n" . pp(@ap);

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@ -0,0 +1,6 @@
(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">additive</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">return</span> <span style="color: #7060A8;">is_prime</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">sum</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">sq_sub</span><span style="color: #0000FF;">(</span><span style="color: #000000;">p</span><span style="color: #0000FF;">,</span><span style="color: #008000;">'0'</span><span style="color: #0000FF;">)))</span> <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">filter</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">apply</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">get_primes_le</span><span style="color: #0000FF;">(</span><span style="color: #000000;">500</span><span style="color: #0000FF;">),</span><span style="color: #7060A8;">sprint</span><span style="color: #0000FF;">),</span><span style="color: #000000;">additive</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%d additive primes found: %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">),</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">shorten</span><span style="color: #0000FF;">(</span><span style="color: #000000;">res</span><span style="color: #0000FF;">,</span><span style="color: #008000;">""</span><span style="color: #0000FF;">,</span><span style="color: #000000;">6</span><span style="color: #0000FF;">))})</span>
<!--

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@ -0,0 +1,26 @@
/# Rosetta Code problem: http://rosettacode.org/wiki/Additive_primes
by Galileo, 05/2022 #/
include ..\Utilitys.pmt
def isprime
dup 1 <= if drop false
else dup 2 == not if
( dup sqrt 2 swap ) for
over swap mod not if drop false exitfor endif
endfor
endif
endif
false == not
enddef
def digitsum
0 swap dup 0 > while dup 10 mod rot + swap 10 / int dup 0 > endwhile
drop
enddef
0 500 for
dup isprime over digitsum isprime and if print " " print 1 + else drop endif
endfor
"Additive primes found: " print print

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@ -0,0 +1,12 @@
main =>
PCount = 0,
foreach (I in 2..499)
if prime(I) && prime(sum_digits(I)) then
PCount := PCount + 1,
printf("%4d ", I)
end
end,
printf("\n\n%d additive primes found.\n", PCount).
sum_digits(N) = S =>
S = sum([ord(C)-ord('0') : C in to_string(N)]).

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@ -0,0 +1,21 @@
(de prime? (N)
(let D 0
(or
(= N 2)
(and
(> N 1)
(bit? 1 N)
(for (D 3 T (+ D 2))
(T (> D (sqrt N)) T)
(T (=0 (% N D)) NIL) ) ) ) ) )
(de additive (N)
(and
(prime? N)
(prime? (sum format (chop N))) ) )
(let C 0
(for (N 0 (> 500 N) (inc N))
(when (additive N)
(printsp N)
(inc 'C) ) )
(prinl)
(prinl "Total count: " C) )

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@ -0,0 +1,36 @@
IntList primes = new IntList();
void setup() {
sieve(500);
int count = 0;
for (int i = 2; i < 500; i++) {
if (primes.hasValue(i) && primes.hasValue(sumDigits(i))) {
print(i + " ");
count++;
}
}
println();
print("Number of additive primes less than 500: " + count);
}
int sumDigits(int n) {
int sum = 0;
for (int i = 0; i <= floor(log(n) / log(10)); i++) {
sum += floor(n / pow(10, i)) % 10;
}
return sum;
}
void sieve(int max) {
for (int i = 2; i <= max; i++) {
primes.append(i);
}
for (int i = 0; i < primes.size(); i++) {
for (int j = i + 1; j < primes.size(); j++) {
if (primes.get(j) % primes.get(i) == 0) {
primes.remove(j);
j--;
}
}
}
}

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@ -0,0 +1,15 @@
#MAX=500
Global Dim P.b(#MAX) : FillMemory(@P(),#MAX,1,#PB_Byte)
If OpenConsole()=0 : End 1 : EndIf
For n=2 To Sqr(#MAX)+1 : If P(n) : m=n*n : While m<=#MAX : P(m)=0 : m+n : Wend : EndIf : Next
Procedure.i qsum(v.i)
While v : qs+v%10 : v/10 : Wend
ProcedureReturn qs
EndProcedure
For i=2 To #MAX
If P(i) And P(qsum(i)) : c+1 : Print(RSet(Str(i),5)) : If c%10=0 : PrintN("") : EndIf : EndIf
Next
PrintN(~"\n\n"+Str(c)+" additive primes below 500.")
Input()

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@ -0,0 +1,29 @@
def is_prime(n: int) -> bool:
if n <= 3:
return n > 1
if n % 2 == 0 or n % 3 == 0:
return False
i = 5
while i ** 2 <= n:
if n % i == 0 or n % (i + 2) == 0:
return False
i += 6
return True
def digit_sum(n: int) -> int:
sum = 0
while n > 0:
sum += n % 10
n //= 10
return sum
def main() -> None:
additive_primes = 0
for i in range(2, 500):
if is_prime(i) and is_prime(digit_sum(i)):
additive_primes += 1
print(i, end=" ")
print(f"\nFound {additive_primes} additive primes less than 500")
if __name__ == "__main__":
main()

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@ -0,0 +1,10 @@
500 eratosthenes
[]
500 times
[ i^ isprime if
[ i^ 10 digitsum
isprime if
[ i^ join ] ] ]
dup echo cr cr
size echo say " additive primes found."

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@ -0,0 +1,44 @@
/*REXX program counts/displays the number of additive primes under a specified number N.*/
parse arg n cols . /*get optional number of primes to find*/
if n=='' | n=="," then n= 500 /*Not specified? Then assume default.*/
if cols=='' | cols=="," then cols= 10 /* " " " " " */
call genP n /*generate all primes under N. */
w= 10 /*width of a number in any column. */
title= " additive primes that are < " commas(n)
if cols>0 then say ' index 'center(title, 1 + cols*(w+1) )
if cols>0 then say ''center("" , 1 + cols*(w+1), '')
found= 0; idx= 1 /*initialize # of additive primes & IDX*/
$= /*a list of additive primes (so far). */
do j=1 for #; p= @.j /*obtain the Jth prime. */
_= sumDigs(p); if \!._ then iterate /*is sum of J's digs a prime? No, skip.*/ /* ◄■■■■■■■■ a filter. */
found= found + 1 /*bump the count of additive primes. */
if cols<0 then iterate /*Build the list (to be shown later)? */
c= commas(p) /*maybe add commas to the number. */
$= $ right(c, max(w, length(c) ) ) /*add additive prime──►list, allow big#*/
if found//cols\==0 then iterate /*have we populated a line of output? */
say center(idx, 7)'' substr($, 2); $= /*display what we have so far (cols). */
idx= idx + cols /*bump the index count for the output*/
end /*j*/
if $\=='' then say center(idx, 7)"" substr($, 2) /*possible display residual output.*/
if cols>0 then say ''center("" , 1 + cols*(w+1), '')
say
say 'found ' commas(found) title
exit 0 /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
commas: parse arg ?; do jc=length(?)-3 to 1 by -3; ?=insert(',', ?, jc); end; return ?
sumDigs: parse arg x 1 s 2; do k=2 for length(x)-1; s= s + substr(x,k,1); end; return s
/*──────────────────────────────────────────────────────────────────────────────────────*/
genP: parse arg n; @.1= 2; @.2= 3; @.3= 5; @.4= 7; @.5= 11; @.6= 13
!.= 0; !.2= 1; !.3= 1; !.5= 1; !.7= 1; !.11= 1; !.13= 1
#= 6; sq.#= @.# ** 2 /*the number of primes; prime squared.*/
do j=@.#+2 by 2 for max(0, n%2-@.#%2-1) /*find odd primes from here on. */
parse var j '' -1 _ /*obtain the last digit of the J var.*/
if _==5 then iterate; if j// 3==0 then iterate /*J ÷ by 5? J ÷ by 3? */
if j// 7==0 then iterate; if j//11==0 then iterate /*" " " 7? " " " 11? */
/* [↓] divide by the primes. ___ */
do k=6 while sq.k<=j /*divide J by other primes ≤ √ J */
if j//@.k==0 then iterate j /*÷ by prev. prime? ¬prime ___ */
end /*k*/ /* [↑] only divide up to √ J */
#= # + 1; @.#= j; sq.#= j*j; !.j= 1 /*bump prime count; assign prime & flag*/
end /*j*/; return

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@ -0,0 +1,14 @@
#lang racket
(require math/number-theory)
(define (sum-of-digits n (σ 0))
(if (zero? n) σ (let-values (((q r) (quotient/remainder n 10)))
(sum-of-digits q (+ σ r)))))
(define (additive-prime? n)
(and (prime? n) (prime? (sum-of-digits n))))
(define additive-primes<500 (filter additive-prime? (range 1 500)))
(printf "There are ~a additive primes < 500~%" (length additive-primes<500))
(printf "They are: ~a~%" additive-primes<500)

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@ -0,0 +1,3 @@
unit sub MAIN ($limit = 500);
say "{+$_} additive primes < $limit:\n{$_».fmt("%" ~ $limit.chars ~ "d").batch(10).join("\n")}",
with ^$limit .grep: { .is-prime and .comb.sum.is-prime }

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@ -0,0 +1,13 @@
cross-sum: function [n][out: 0 foreach m form n [out: out + to-integer to-string m]]
additive-primes: function [n][collect [foreach p ps: primes n [if find ps cross-sum p [keep p]]]]
length? probe new-line/skip additive-primes 500 true 10
[
2 3 5 7 11 23 29 41 43 47
61 67 83 89 101 113 131 137 139 151
157 173 179 191 193 197 199 223 227 229
241 263 269 281 283 311 313 317 331 337
353 359 373 379 397 401 409 421 443 449
461 463 467 487
]
== 54

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@ -0,0 +1,27 @@
load "stdlib.ring"
see "working..." + nl
see "Additive primes are:" + nl
row = 0
limit = 500
for n = 1 to limit
num = 0
if isprime(n)
strn = string(n)
for m = 1 to len(strn)
num = num + number(strn[m])
next
if isprime(num)
row = row + 1
see "" + n + " "
if row%10 = 0
see nl
ok
ok
ok
next
see nl + "found " + row + " additive primes." + nl
see "done..." + nl

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@ -0,0 +1,8 @@
require "prime"
additive_primes = Prime.lazy.select{|prime| prime.digits.sum.prime? }
N = 500
res = additive_primes.take_while{|n| n < N}.to_a
puts res.join(" ")
puts "\n#{res.size} additive primes below #{N}."

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@ -0,0 +1,17 @@
fn main() {
let limit = 500;
let column_w = limit.to_string().len() + 1;
let mut pms = Vec::with_capacity(limit / 2 - limit / 3 / 2 - limit / 5 / 3 / 2 + 1);
let mut count = 0;
for u in (2..3).chain((3..limit).step_by(2)) {
if pms.iter().take_while(|&&p| p * p <= u).all(|&p| u % p != 0) {
pms.push(u);
let dgs = std::iter::successors(Some(u), |&n| (n > 9).then(|| n / 10)).map(|n| n % 10);
if pms.binary_search(&dgs.sum()).is_ok() {
print!("{}{u:column_w$}", if count % 10 == 0 { "\n" } else { "" });
count += 1;
}
}
}
println!("\n---\nFound {count} additive primes less than {limit}");
}

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@ -0,0 +1,19 @@
// [dependencies]
// primal = "0.3.0"
fn sum_digits(u: usize) -> usize {
std::iter::successors(Some(u), |&n| (n > 9).then(|| n / 10)).fold(0, |s, n| s + n % 10)
}
fn main() {
let limit = 500;
let column_w = limit.to_string().len() + 1;
let sieve_primes = primal::Sieve::new(limit);
let count = sieve_primes
.primes_from(2)
.filter(|&p| p < limit && sieve_primes.is_prime(sum_digits(p)))
.zip(["\n"].iter().chain(&[""; 9]).cycle())
.inspect(|(u, sn)| print!("{sn}{u:column_w$}"))
.count();
println!("\n---\nFound {count} additive primes less than {limit}");
}

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@ -0,0 +1,5 @@
limit = 500
additivePrimes = list(filter(lambda x: x > 0,
list(map(lambda x: int(x) if sum([int(digit) for digit in x]) in Primes() else 0,
list(map(str,list(primes(1,limit))))))))
print(f"{additivePrimes}\nFound {len(additivePrimes)} additive primes less than {limit}")

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@ -0,0 +1,46 @@
$ include "seed7_05.s7i";
const func boolean: isPrime (in integer: number) is func
result
var boolean: prime is FALSE;
local
var integer: upTo is 0;
var integer: testNum is 3;
begin
if number = 2 then
prime := TRUE;
elsif odd(number) and number > 2 then
upTo := sqrt(number);
while number rem testNum <> 0 and testNum <= upTo do
testNum +:= 2;
end while;
prime := testNum > upTo;
end if;
end func;
const func integer: digitSum (in var integer: number) is func
result
var integer: sum is 0;
begin
while number > 0 do
sum +:= number rem 10;
number := number div 10;
end while;
end func;
const proc: main is func
local
var integer: n is 0;
var integer: count is 0;
begin
for n range 2 to 499 do
if isPrime(n) and isPrime(digitSum(n)) then
write(n lpad 3 <& " ");
incr(count);
if count rem 9 = 0 then
writeln;
end if;
end if;
end for;
writeln("\nFound " <& count <& " additive primes < 500.");
end func;

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@ -0,0 +1,7 @@
func additive_primes(upto, base = 10) {
upto.primes.grep { .sumdigits(base).is_prime }
}
additive_primes(500).each_slice(10, {|*a|
a.map { '%3s' % _ }.join(' ').say
})

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@ -0,0 +1,46 @@
import Foundation
func isPrime(_ n: Int) -> Bool {
if n < 2 {
return false
}
if n % 2 == 0 {
return n == 2
}
if n % 3 == 0 {
return n == 3
}
var p = 5
while p * p <= n {
if n % p == 0 {
return false
}
p += 2
if n % p == 0 {
return false
}
p += 4
}
return true
}
func digitSum(_ num: Int) -> Int {
var sum = 0
var n = num
while n > 0 {
sum += n % 10
n /= 10
}
return sum
}
let limit = 500
print("Additive primes less than \(limit):")
var count = 0
for n in 1..<limit {
if isPrime(digitSum(n)) && isPrime(n) {
count += 1
print(String(format: "%3d", n), terminator: count % 10 == 0 ? "\n" : " ")
}
}
print("\n\(count) additive primes found.")

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@ -0,0 +1,107 @@
INTEGER PROC FNMathGetSquareRootI( INTEGER xI )
INTEGER squareRootI = 0
IF ( xI > 0 )
WHILE( ( squareRootI * squareRootI ) <= xI )
squareRootI = squareRootI + 1
ENDWHILE
squareRootI = squareRootI - 1
ENDIF
RETURN( squareRootI )
END
//
INTEGER PROC FNMathCheckIntegerIsPrimeB( INTEGER nI )
INTEGER I = 0
INTEGER primeB = FALSE
INTEGER stopB = FALSE
INTEGER restI = 0
INTEGER limitI = 0
primeB = FALSE
IF ( nI <= 0 )
RETURN( FALSE )
ENDIF
IF ( nI == 1 )
RETURN( FALSE )
ENDIF
IF ( nI == 2 )
RETURN( TRUE )
ENDIF
IF ( nI == 3 )
RETURN( TRUE )
ENDIF
IF ( nI MOD 2 == 0 )
RETURN( FALSE )
ENDIF
IF ( ( nI MOD 6 ) <> 1 ) AND ( ( nI MOD 6 ) <> 5 )
RETURN( FALSE )
ENDIF
limitI = FNMathGetSquareRootI( nI )
I = 3
REPEAT
restI = ( nI MOD I )
IF ( restI == 0 )
primeB = FALSE
stopB = TRUE
ENDIF
IF ( I > limitI )
primeB = TRUE
stopB = TRUE
ENDIF
I = I + 2
UNTIL ( stopB )
RETURN( primeB )
END
//
INTEGER PROC FNMathCheckIntegerDigitSumI( INTEGER J )
STRING s[255] = Str( J )
STRING cS[255] = ""
INTEGER minI = 1
INTEGER maxI = Length( s )
INTEGER I = 0
INTEGER K = 0
FOR I = minI TO maxI
cS = s[ I ]
K = K + Val( cS )
ENDFOR
RETURN( K )
END
//
INTEGER PROC FNMathCheckIntegerDigitSumIsPrimeB( INTEGER I )
INTEGER J = FNMathCheckIntegerDigitSumI( I )
INTEGER B = FNMathCheckIntegerIsPrimeB( J )
RETURN( B )
END
//
INTEGER PROC FNMathGetPrimeAdditiveAllToBufferB( INTEGER maxI, INTEGER bufferI )
INTEGER B = FALSE
INTEGER B1 = FALSE
INTEGER B2 = FALSE
INTEGER B3 = FALSE
INTEGER minI = 2
INTEGER I = 0
FOR I = minI TO maxI
B1 = FNMathCheckIntegerIsPrimeB( I )
B2 = FNMathCheckIntegerDigitSumIsPrimeB( I )
B3 = B1 AND B2
IF ( B3 )
PushPosition()
PushBlock()
GotoBufferId( bufferI )
AddLine( Str( I ) )
PopBlock()
PopPosition()
ENDIF
ENDFOR
B = TRUE
RETURN( B )
END
//
PROC Main()
STRING s1[255] = "500" // change this
INTEGER bufferI = 0
PushPosition()
bufferI = CreateTempBuffer()
PopPosition()
IF ( NOT ( Ask( " = ", s1, _EDIT_HISTORY_ ) ) AND ( Length( s1 ) > 0 ) ) RETURN() ENDIF
Message( FNMathGetPrimeAdditiveAllToBufferB( Val( s1 ), bufferI ) ) // gives e.g. TRUE
GotoBufferId( bufferI )
END

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@ -0,0 +1,56 @@
fn is_prime(n int) bool {
if n < 2 {
return false
} else if n%2 == 0 {
return n == 2
} else if n%3 == 0 {
return n == 3
} else {
mut d := 5
for d*d <= n {
if n%d == 0 {
return false
}
d += 2
if n%d == 0 {
return false
}
d += 4
}
return true
}
}
fn sum_digits(nn int) int {
mut n := nn
mut sum := 0
for n > 0 {
sum += n % 10
n /= 10
}
return sum
}
fn main() {
println("Additive primes less than 500:")
mut i := 2
mut count := 0
for {
if is_prime(i) && is_prime(sum_digits(i)) {
count++
print("${i:3} ")
if count%10 == 0 {
println('')
}
}
if i > 2 {
i += 2
} else {
i++
}
if i > 499 {
break
}
}
println("\n\n$count additive primes found.")
}

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@ -0,0 +1,34 @@
10 M=499
20 :1)=1
30 P=2
40 :P)=0
50 P=P+1
60 #=M>P*40
70 P=2
80 C=P*2
90 :C)=1
110 C=C+P
120 #=M>C*90
130 P=P+1
140 #=M/2>P*80
150 P=2
160 N=0
170 #=:P)*290
180 S=0
190 K=P
200 K=K/10
210 S=S+%
220 #=0<K*200
230 #=:S)*290
240 ?=P
250 $=9
260 N=N+1
270 #=N/10*0+%=0=0*290
280 ?=""
290 P=P+1
300 #=M>P*170
310 ?=""
320 ?="There are ";
330 ?=N
340 ?=" additive primes below ";
350 ?=M+1

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@ -0,0 +1,23 @@
import "/math" for Int
import "/fmt" for Fmt
var sumDigits = Fn.new { |n|
var sum = 0
while (n > 0) {
sum = sum + (n % 10)
n = (n/10).floor
}
return sum
}
System.print("Additive primes less than 500:")
var primes = Int.primeSieve(499)
var count = 0
for (p in primes) {
if (Int.isPrime(sumDigits.call(p))) {
count = count + 1
Fmt.write("$3d ", p)
if (count % 10 == 0) System.print()
}
}
System.print("\n\n%(count) additive primes found.")

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func IsPrime(N); \Return 'true' if N is a prime number
int N, I;
[if N <= 1 then return false;
for I:= 2 to sqrt(N) do
if rem(N/I) = 0 then return false;
return true;
];
func SumDigits(N); \Return the sum of the digits in N
int N, Sum;
[Sum:= 0;
repeat N:= N/10;
Sum:= Sum + rem(0);
until N=0;
return Sum;
];
int Count, N;
[Count:= 0;
for N:= 0 to 500-1 do
if IsPrime(N) & IsPrime(SumDigits(N)) then
[IntOut(0, N);
Count:= Count+1;
if rem(Count/10) = 0 then CrLf(0) else ChOut(0, 9\tab\);
];
CrLf(0);
IntOut(0, Count);
Text(0, " additive primes found below 500.
");
]

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// Rosetta Code problem: http://rosettacode.org/wiki/Additive_primes
// by Galileo, 06/2022
limit = 500
dim flags(limit)
for i = 2 to limit
for k = i*i to limit step i
flags(k) = 1
next
if flags(i) = 0 primes$ = primes$ + str$(i) + " "
next
dim prim$(1)
n = token(primes$, prim$())
for i = 1 to n
sum = 0
num$ = prim$(i)
for j = 1 to len(num$)
sum = sum + val(mid$(num$, j, 1))
next
if instr(primes$, str$(sum) + " ") print prim$(i), " "; : count = count + 1
next
print "\nFound: ", count