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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/Arithmetic_numbers

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;Definition
A positive integer '''n''' is an arithmetic number if the average of its positive divisors is also an integer.
Clearly all odd primes '''p''' must be arithmetic numbers because their only divisors are '''1''' and '''p''' whose sum is even and hence their average must be an integer. However, the prime number '''2''' is not an arithmetic number because the average of its divisors is 1.5.
;Example
30 is an arithmetic number because its 7 divisors are: [1, 2, 3, 5, 6, 10, 15, 30], their sum is 72 and average 9 which is an integer.
;Task
Calculate and show here:
1. The first 100 arithmetic numbers.
2. The '''x'''th arithmetic number where '''x''' = 1,000 and '''x''' = 10,000.
3. How many of the first '''x''' arithmetic numbers are composite.
Note that, technically, the arithmetic number '''1''' is neither prime nor composite.
;Stretch
Carry out the same exercise in 2. and 3. above for '''x''' = 100,000 and '''x''' = 1,000,000.
;References
* [[wp:Arithmetic_number|Wikipedia: Arithmetic number]]
* [[oeis:A003601|OEIS:A003601 - Numbers n such that the average of the divisors of n is an integer]]
<br><br>

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F factors(Int n)
V f = Set([1, n])
V i = 2
L
V j = n I/ i
I j < i
L.break
I i * j == n
f.add(i)
f.add(j)
i++
R f
V arithmetic_count = 0
V composite_count = 0
V n = 1
L arithmetic_count <= 1000000
V f = factors(n)
I sum(f) % f.len == 0
arithmetic_count++
I f.len > 2
composite_count++
I arithmetic_count <= 100
print(f:{n:3} , end' )
I arithmetic_count % 10 == 0
print()
I arithmetic_count C (1000, 10000, 100000, 1000000)
print("\n"arithmetic_countth arithmetic number is n)
print(Number of composite arithmetic numbers <= n: composite_count)
n++

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BEGIN # find arithmetic numbers - numbers whose average divisor is an integer #
# i.e. sum of divisors MOD count of divisors = 0 #
INT max number = 500 000; # maximum number we will consider #
[ 1 : max number ]INT d sum;
[ 1 : max number ]INT d count;
# all positive integers are divisible by 1 and so have at least 1 divisor #
FOR i TO max number DO d sum[ i ] := d count[ i ] := 1 OD;
# construct the divisor sums and counts #
FOR i FROM 2 TO max number DO
FOR j FROM i BY i TO max number DO
d count[ j ] +:= 1;
d sum[ j ] +:= i
OD
OD;
# count arithmetic numbers, and show the first 100, the 1 000th, 10 000th #
# and the 100 000th and show how many are composite #
INT max arithmetic = 100 000;
INT a count := 0;
INT c count := 0;
FOR i TO max number WHILE a count < max arithmetic DO
IF d sum[ i ] MOD d count[ i ] = 0 THEN
# have an arithmetic number #
IF d count[ i ] > 2 THEN
# the number is composite #
c count +:= 1
FI;
a count +:= 1;
IF a count <= 100 THEN
print( ( " ", whole( i, -3 ) ) );
IF a count MOD 10 = 0 THEN print( ( newline ) ) FI
ELIF a count = 1 000
OR a count = 10 000
OR a count = 100 000
THEN
print( ( newline ) );
print( ( "The ", whole( a count, 0 )
, "th arithmetic number is: ", whole( i, 0 )
, newline
)
);
print( ( " There are ", whole( c count, 0 )
, " composite arithmetic numbers up to ", whole( i, 0 )
, newline
)
)
FI
FI
OD
END

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with Ada.Text_IO; use Ada.Text_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
procedure Main is
procedure divisor_count_and_sum
(n : Positive; divisor_count : out Natural; divisor_sum : out Natural)
is
I : Positive := 1;
J : Natural;
begin
divisor_count := 0;
divisor_sum := 0;
loop
J := n / I;
exit when J < I;
if I * J = n then
divisor_sum := divisor_sum + I;
divisor_count := divisor_count + 1;
if I /= J then
divisor_sum := divisor_sum + J;
divisor_count := divisor_count + 1;
end if;
end if;
I := I + 1;
end loop;
end divisor_count_and_sum;
arithmetic_count : Natural := 0;
composite_count : Natural := 0;
div_count : Natural;
div_sum : Natural;
mean : Natural;
n : Positive := 1;
begin
while arithmetic_count <= 1_000_000 loop
divisor_count_and_sum (n, div_count, div_sum);
mean := div_sum / div_count;
if mean * div_count = div_sum then
arithmetic_count := arithmetic_count + 1;
if div_count > 2 then
composite_count := composite_count + 1;
end if;
if arithmetic_count <= 100 then
Put (Item => n, Width => 4);
if arithmetic_count mod 10 = 0 then
New_Line;
end if;
end if;
if arithmetic_count = 1_000 or else arithmetic_count = 10_000
or else arithmetic_count = 100_000
or else arithmetic_count = 1_000_000
then
New_Line;
Put (Item => arithmetic_count, Width => 1);
Put_Line ("th arithmetic number is" & n'Image);
Put_Line
("Number of composite arithmetic numbers <=" & n'Image & ":" &
composite_count'Image);
end if;
end if;
n := n + 1;
end loop;
end Main;

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arithmetic?: function [n][
avg: average factors n
zero? abs avg - to :integer avg
]
composite?: function [n]->
not? prime? n
arithmeticsUpTo: function [lim][
items: select.first: lim 1..∞ => arithmetic?
print [(to :string lim)++"th" "arithmetic number:" last items]
print ["Number of composite arithmetic numbers <= " last items ":" dec enumerate items => composite?]
print ""
]
first100: select.first:100 1..∞ => arithmetic?
loop split.every: 10 first100 'x ->
print map x 's -> pad to :string s 4
print ""
arithmeticsUpTo 1000
arithmeticsUpTo 10000
; stretch goal
arithmeticsUpTo 100000
arithmeticsUpTo 1000000

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ArithmeticNumbers(n, mx:=0){
c := composite := 0
loop
{
num := A_Index, sum := 0
x := Factors(num)
for i, v in x
sum += v
av := sum / x.Count()
if (av = Floor(av))
{
res .= c++ <= 100 ? SubStr(" " num, -2) (mod(c, 25) ? " " : "`n") : ""
composite += x.Count() > 2 ? 1 : 0
}
if (c = n) || (c = mx)
break
}
return [n?num:res, composite]
}
Factors(n){
Loop, % floor(sqrt(n))
v := A_Index = 1 ? 1 "," n : mod(n,A_Index) ? v : v "," A_Index "," n//A_Index
Sort, v, N U D,
Return StrSplit(v, ",")
}

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MsgBox % Result := "The first 100 arithmetic numbers:`n"
. ArithmeticNumbers(0, 100).1
. "`nThe 1000th arithmetic number: "
. ArithmeticNumbers(1000).1
. "`tcomposites = "
. ArithmeticNumbers(1000).2
. "`nThe 10000th arithmetic number: "
. ArithmeticNumbers(10000).1
. "`tcomposites = "
. ArithmeticNumbers(10000).2

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#include <cstdio>
void divisor_count_and_sum(unsigned int n,
unsigned int& divisor_count,
unsigned int& divisor_sum)
{
divisor_count = 0;
divisor_sum = 0;
for (unsigned int i = 1;; i++)
{
unsigned int j = n / i;
if (j < i)
break;
if (i * j != n)
continue;
divisor_sum += i;
divisor_count += 1;
if (i != j)
{
divisor_sum += j;
divisor_count += 1;
}
}
}
int main()
{
unsigned int arithmetic_count = 0;
unsigned int composite_count = 0;
for (unsigned int n = 1; arithmetic_count <= 1000000; n++)
{
unsigned int divisor_count;
unsigned int divisor_sum;
divisor_count_and_sum(n, divisor_count, divisor_sum);
unsigned int mean = divisor_sum / divisor_count;
if (mean * divisor_count != divisor_sum)
continue;
arithmetic_count++;
if (divisor_count > 2)
composite_count++;
if (arithmetic_count <= 100)
{
// would prefer to use <stream> and <format> in C++20
std::printf("%3u ", n);
if (arithmetic_count % 10 == 0)
std::printf("\n");
}
if ((arithmetic_count == 1000) || (arithmetic_count == 10000) ||
(arithmetic_count == 100000) || (arithmetic_count == 1000000))
{
std::printf("\n%uth arithmetic number is %u\n", arithmetic_count, n);
std::printf("Number of composite arithmetic numbers <= %u: %u\n", n, composite_count);
}
}
return 0;
}

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#include <stdio.h>
void divisor_count_and_sum(unsigned int n, unsigned int* pcount,
unsigned int* psum) {
unsigned int divisor_count = 1;
unsigned int divisor_sum = 1;
unsigned int power = 2;
for (; (n & 1) == 0; power <<= 1, n >>= 1) {
++divisor_count;
divisor_sum += power;
}
for (unsigned int p = 3; p * p <= n; p += 2) {
unsigned int count = 1, sum = 1;
for (power = p; n % p == 0; power *= p, n /= p) {
++count;
sum += power;
}
divisor_count *= count;
divisor_sum *= sum;
}
if (n > 1) {
divisor_count *= 2;
divisor_sum *= n + 1;
}
*pcount = divisor_count;
*psum = divisor_sum;
}
int main() {
unsigned int arithmetic_count = 0;
unsigned int composite_count = 0;
for (unsigned int n = 1; arithmetic_count <= 1000000; ++n) {
unsigned int divisor_count;
unsigned int divisor_sum;
divisor_count_and_sum(n, &divisor_count, &divisor_sum);
if (divisor_sum % divisor_count != 0)
continue;
++arithmetic_count;
if (divisor_count > 2)
++composite_count;
if (arithmetic_count <= 100) {
printf("%3u ", n);
if (arithmetic_count % 10 == 0)
printf("\n");
}
if (arithmetic_count == 1000 || arithmetic_count == 10000 ||
arithmetic_count == 100000 || arithmetic_count == 1000000) {
printf("\n%uth arithmetic number is %u\n", arithmetic_count, n);
printf("Number of composite arithmetic numbers <= %u: %u\n", n,
composite_count);
}
}
return 0;
}

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{{works with| Delphi-6 or better}}
program ArithmeiticNumbers;
{$APPTYPE CONSOLE}
procedure ArithmeticNumbers;
var N, ArithCnt, CompCnt, DDiv: integer;
var DivCnt, Sum, Quot, Rem: integer;
begin
N:= 1; ArithCnt:= 0; CompCnt:= 0;
repeat
begin
DDiv:= 1; DivCnt:= 0; Sum:= 0;
while true do
begin
Quot:= N div DDiv;
Rem:=N mod DDiv;
if Quot < DDiv then break;
if (Quot = DDiv) and (Rem = 0) then //N is a square
begin
Sum:= Sum+Quot;
DivCnt:= DivCnt+1;
break;
end;
if Rem = 0 then
begin
Sum:= Sum + DDiv + Quot;
DivCnt:= DivCnt+2;
end;
DDiv:= DDiv+1;
end;
if (Sum mod DivCnt) = 0 then //N is arithmetic
begin
ArithCnt:= ArithCnt+1;
if ArithCnt <= 100 then
begin
Write(N:4);
if (ArithCnt mod 20) = 0 then WriteLn;
end;
if DivCnt > 2 then CompCnt:= CompCnt+1;
case ArithCnt of 1000, 10000, 100000, 1000000:
begin
Writeln;
Write(N, #9 {tab} );
Write(CompCnt);
end;
end;
end;
N:= N+1;
end
until ArithCnt >= 1000000;
WriteLn;
end;
begin
ArithmeticNumbers;
WriteLn('Hit Any Key');
ReadLn;
end.

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print "The first 100 arithmetic numbers are:"
numfmt 0 3
n = 1
while aricnt <= 1e5
divi = 1 ; divcnt = 0 ; sum = 0
repeat
quot = n div divi
until quot < divi
if quot = divi and n mod divi = 0
sum += quot
divcnt += 1
break 1
.
if n mod divi = 0
sum += divi + quot
divcnt += 2
.
divi += 1
.
if sum mod divcnt = 0
aricnt += 1
if aricnt <= 100
write n & " "
if aricnt mod 10 = 0
print ""
.
.
if divcnt > 2
compcnt += 1
.
if aricnt = 1e3 or aricnt = 1e4 or aricnt = 1e5
print ""
print aricnt & "th arithmetic number: " & n
print "Composite arithmetic numbers: " & compcnt
.
.
n += 1
.

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USING: combinators formatting grouping io kernel lists
lists.lazy math math.functions math.primes math.primes.factors
math.statistics math.text.english prettyprint sequences
tools.memory.private ;
: arith? ( n -- ? ) divisors mean integer? ;
: larith ( -- list ) 1 lfrom [ arith? ] lfilter ;
: arith ( m -- seq ) larith ltake list>array ;
: composite? ( n -- ? ) dup 1 > swap prime? not and ;
: ordinal ( n -- str ) [ commas ] keep ordinal-suffix append ;
: info. ( n -- )
{
[ ordinal "%s arithmetic number: " printf ]
[ arith dup last commas print ]
[ commas "Number of composite arithmetic numbers <= %s: " printf ]
[ drop [ composite? ] count commas print nl ]
} cleave ;
"First 100 arithmetic numbers:" print
100 arith 10 group simple-table. nl
{ 3 4 5 6 } [ 10^ info. ] each

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program ArithmeticNumbers;
{$OPTIMIZATION ON,ALL}
type
tPrimeFact = packed record
pfSumOfDivs,
pfRemain : Uint64;
pfDivCnt : Uint32;
pfMaxIdx : Uint32;
pfpotPrimIdx : array[0..9] of word;
pfpotMax : array[0..11] of byte;//11 instead of 9 for alignment
end;
var
SmallPrimes : array[0..6541] of word;
procedure InitSmallPrimes;
var
testPrime,j,p,idx:Uint32;
begin
SmallPrimes[0] := 2;
SmallPrimes[1] := 3;
idx := 1;
testPrime := 5;
repeat
For j := 1 to idx do
begin
p := SmallPrimes[j];
if p*p>testPrime then
BREAK;
if testPrime mod p = 0 then
Begin
p := 0;
BREAK;
end;
end;
if p <> 0 then
begin
inc(idx);
SmallPrimes[idx]:= testPrime;
end;
inc(testPrime,2);
until testPrime >= 65535;
end;
procedure smplPrimeDecomp(var PrimeFact:tPrimeFact;n:Uint32);
var
pr,i,pot,fac,q :NativeUInt;
Begin
with PrimeFact do
Begin
pfDivCnt := 1;
pfSumOfDivs := 1;
pfRemain := n;
pfMaxIdx := 0;
pfpotPrimIdx[0] := 1;
pfpotMax[0] := 0;
i := 0;
while i < High(SmallPrimes) do
begin
pr := SmallPrimes[i];
q := n DIV pr;
//if n < pr*pr
if pr > q then
BREAK;
if n = pr*q then
Begin
pfpotPrimIdx[pfMaxIdx] := i;
pot := 0;
fac := pr;
repeat
n := q;
q := n div pr;
pot+=1;
fac *= pr;
until n <> pr*q;
pfpotMax[pfMaxIdx] := pot;
pfDivCnt *= pot+1;
pfSumOfDivs *= (fac-1)DIV(pr-1);
inc(pfMaxIdx);
end;
inc(i);
end;
pfRemain := n;
if n > 1 then
Begin
pfDivCnt *= 2;
pfSumOfDivs *= n+1
end;
end;
end;
function IsArithmetic(const PrimeFact:tPrimeFact):boolean;inline;
begin
with PrimeFact do
IsArithmetic := pfSumOfDivs mod pfDivCnt = 0;
end;
var
pF :TPrimeFact;
i,cnt,primeCnt,lmt : Uint32;
begin
InitSmallPrimes;
writeln('First 100 arithemetic numbers');
cnt := 0;
i := 1;
repeat
smplPrimeDecomp(pF,i);
if IsArithmetic(pF) then
begin
write(i:4);
inc(cnt);
if cnt MOD 20 =0 then
writeln;
end;
inc(i);
until cnt = 100;
writeln;
writeln(' Arithemetic numbers');
writeln(' Index number composite');
cnt := 0;
primeCnt := 0;
lmt := 10;
i := 1;
repeat
smplPrimeDecomp(pF,i);
if IsArithmetic(pF) then
begin
inc(cnt);
if pF.pfRemain = i then
inc(primeCnt);
end;
if cnt = lmt then
begin
writeln(lmt:8,i:9,lmt-primeCnt:10);
lmt := lmt*10;
end;
inc(i);
until lmt>1000000;
{$IFdef WINDOWS}
WriteLn('Hit <ENTER>');ReadLn;
{$ENDIF}
end.

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const
//make size of sieve using 11 MB of 16MB Level III cache
SizePrDeFe = 192*1024;
.....
function IsArithmetic(const PrimeFact:tPrimeFac):boolean;inline;
begin
with PrimeFact do
IsArithmetic := pfSumOfDivs mod pfDivCnt = 0;
end;
var
pPrimeDecomp :tpPrimeFac;
T0:Int64;
n,lmt,cnt,primeCnt : NativeUInt;
Begin
InitSmallPrimes;
T0 := GetTickCount64;
cnt := 1;
primeCnt := 1;
lmt := 10;
n := 2;
Init_Sieve(n);
repeat
pPrimeDecomp:= GetNextPrimeDecomp;
if IsArithmetic(pPrimeDecomp^) then
begin
inc(cnt);
if pPrimeDecomp^.pfDivCnt = 2 then
inc(primeCnt);
end;
if cnt = lmt then
begin
writeln(lmt:14,n:14,lmt-primeCnt:14);
lmt := lmt*10;
end;
inc(n);
until lmt>1000*1000*1000;
T0 := GetTickCount64-T0;
writeln;
end.

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' Rosetta Code problem: https://rosettacode.org/wiki/Arithmetic_numbers
' by Jjuanhdez, 06/2022
Dim As Double t0 = Timer
Dim As Integer N = 1, ArithCnt = 0, CompCnt = 0
Dim As Integer Div, DivCnt, Sum, Quot
Print "The first 100 arithmetic numbers are:"
Do
Div = 1 : DivCnt = 0 : Sum = 0
Do
Quot = N / Div
If Quot < Div Then Exit Do
If Quot = Div AndAlso (N Mod Div) = 0 Then 'N is a square
Sum += Quot
DivCnt += 1
Exit Do
End If
If (N Mod Div) = 0 Then
Sum += Div + Quot
DivCnt += 2
End If
Div += 1
Loop
If (Sum Mod DivCnt) = 0 Then 'N is arithmetic
ArithCnt += 1
If ArithCnt <= 100 Then
Print Using "####"; N;
If (ArithCnt Mod 20) = 0 Then Print
End If
If DivCnt > 2 Then CompCnt += 1
Select Case ArithCnt
Case 1e3
Print Using !"\nThe #######th arithmetic number is #####,### up to which ###,### are composite."; ArithCnt; N; CompCnt
Case 1e4, 1e5, 1e6
Print Using "The #######th arithmetic number is #####,### up to which ###,### are composite."; ArithCnt; N; CompCnt
End Select
End If
N += 1
Loop Until ArithCnt >= 1e6
Print !"\nTook"; Timer - t0; " seconds on i5 @3.20 GHz"
Sleep

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' Rosetta Code problem: https://rosettacode.org/wiki/Arithmetic_numbers
' by Rich Love, 9/21/22
' FutureBasic 7.0.14
output file "Arithmetic numbers.app"
Dim As long N = 1, ArithCnt = 0, CompCnt = 0
Dim As long Div, DivCnt, Sum, Quot
toolbox Microseconds( UnsignedWide * microTickCount )
dim as UnsignedWide Time1, Time2
window 1, @"Arithmetic numbers",(0,0,600,200)
Print "The first 100 arithmetic numbers are:"
Microseconds( @Time1 ) //start time
for N = 1 to 2000000)
Div = 1 : DivCnt = 0 : Sum = 0
while 1
Quot = N / Div
If Quot < Div Then Exit while
If Quot = Div And (N Mod Div) = 0 'N is a square
Sum += Quot
DivCnt += 1
Exit while
End If
If (N Mod Div) = 0
Sum += Div + Quot
DivCnt += 2
End If
Div ++
wend
If (Sum Mod DivCnt) = 0 'N is arithmetic
ArithCnt ++
If ArithCnt <= 100
Print Using "####"; N;
If (ArithCnt Mod 20) = 0 Then PRINT
End If
If DivCnt > 2 Then CompCnt ++
Select Case ArithCnt
Case 1e3
PRINT
PRINT USING "The #######th arithmetic number is";ArithCnt;
PRINT USING "#####,### up to which ";N;
PRINT USING "###,### are composite. ";compcnt
Case 1e4, 1e5, 1e6
PRINT USING "The #######th arithmetic number is";ArithCnt;
PRINT USING "#####,### up to which ";N;
PRINT USING "###,### are composite. ";compcnt
End Select
if ArithCnt = 1e6 then exit next
End If
next N
Microseconds( @Time2 ) //end time
float TimeTaken
TimeTaken = (Time2.lo-Time1.lo)/1000/100/10
print
print "It took " + str$(TimeTaken) + " seconds to complete." // Approx 1.2 seconds on a M1 Mac Mini ( Macmini9,1 )
handleevents

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package main
import (
"fmt"
"math"
"rcu"
"sort"
)
func main() {
arithmetic := []int{1}
primes := []int{}
limit := int(1e6)
for n := 3; len(arithmetic) < limit; n++ {
divs := rcu.Divisors(n)
if len(divs) == 2 {
primes = append(primes, n)
arithmetic = append(arithmetic, n)
} else {
mean := float64(rcu.SumInts(divs)) / float64(len(divs))
if mean == math.Trunc(mean) {
arithmetic = append(arithmetic, n)
}
}
}
fmt.Println("The first 100 arithmetic numbers are:")
rcu.PrintTable(arithmetic[0:100], 10, 3, false)
for _, x := range []int{1e3, 1e4, 1e5, 1e6} {
last := arithmetic[x-1]
lastc := rcu.Commatize(last)
fmt.Printf("\nThe %sth arithmetic number is: %s\n", rcu.Commatize(x), lastc)
pcount := sort.SearchInts(primes, last) + 1
if !rcu.IsPrime(last) {
pcount--
}
comp := x - pcount - 1 // 1 is not composite
compc := rcu.Commatize(comp)
fmt.Printf("The count of such numbers <= %s which are composite is %s.\n", lastc, compc)
}
}

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factors=: {{ */@>,{(^ [:i.1+])&.>/__ q:y}}
isArith=: {{ (= <.) (+/%#) factors|y}}"0

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examples=: 1+I.isArith 1+i.2e6
10 10$examples
1 3 5 6 7 11 13 14 15 17
19 20 21 22 23 27 29 30 31 33
35 37 38 39 41 42 43 44 45 46
47 49 51 53 54 55 56 57 59 60
61 62 65 66 67 68 69 70 71 73
77 78 79 83 85 86 87 89 91 92
93 94 95 96 97 99 101 102 103 105
107 109 110 111 113 114 115 116 118 119
123 125 126 127 129 131 132 133 134 135
137 138 139 140 141 142 143 145 147 149
(1e3-1){examples NB. 0 is first
1361
(1e4-1){examples
12953
+/0=1 p: (1e3 {. examples) -. 1
782
+/0=1 p: (1e4 {. examples) -. 1
8458
+/0=1 p: (1e5 {. examples) -. 1
88219
+/0=1 p: (1e6 {. examples) -. 1
905043

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import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public final class ArithmeticNumbers {
public static void main(String[] aArgs) {
int arithmeticCount = 0;
int compositeCount = 0;
int n = 1;
while ( arithmeticCount <= 1_000_000 ) {
Set<Integer> factors = factors(n);
final int sum = factors.stream().mapToInt(Integer::intValue).sum();
if ( sum % factors.size() == 0 ) {
arithmeticCount += 1;
if ( factors.size() > 2 ) {
compositeCount += 1;
}
if ( arithmeticCount <= 100 ) {
System.out.print(String.format("%3d%s", n, ( arithmeticCount % 10 == 0 ) ? "\n" : " "));
}
if ( List.of( 1_000, 10_000, 100_000, 1_000_000 ).contains(arithmeticCount) ) {
System.out.println();
System.out.println(arithmeticCount + "th arithmetic number is " + n);
System.out.println("Number of composite arithmetic numbers <= " + n + ": " + compositeCount);
}
}
n += 1;
}
}
private static Set<Integer> factors(int aNumber) {
Set<Integer> result = Stream.of(1, aNumber).collect(Collectors.toCollection(HashSet::new));
int i = 2;
int j;
while ( ( j = aNumber / i ) >= i ) {
if ( i * j == aNumber ) {
result.add(i);
result.add(j);
}
i += 1;
}
return result;
}
}

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@ -0,0 +1,6 @@
# For the sake of gojq
def _nwise($n):
def nw: if length <= $n then . else .[0:$n] , (.[$n:] | nw) end;
nw;
def lpad($len): tostring | ($len - length) as $l | (" " * $l)[:$l] + .;

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@ -0,0 +1,21 @@
# proper_divisors returns a stream of unordered proper divisors of the input integer.
def proper_divisors:
. as $n
| if $n > 1 then 1,
( range(2; 1 + (sqrt|floor)) as $i
| if ($n % $i) == 0 then $i,
(($n / $i) | if . == $i then empty else . end)
else empty
end)
else empty
end;
def composite:
[limit(2; proper_divisors)] | length == 2;
def arithmetic_numbers:
def average_is_integral(s):
reduce s as $_ ({}; .sum += $_ | .n += 1)
| (.sum % .n) == 0;
1, (range(2; infinite) | select(average_is_integral(., proper_divisors)));

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@ -0,0 +1,18 @@
def task1($limit):
[limit($limit; arithmetic_numbers)] | _nwise(10) | map(lpad(4)) | join(" ");
# $points should be a stream of integers, in order, specifying the reporting points
def task2($points):
last($points) as $last
| label $out
| foreach arithmetic_numbers as $n ({count:0};
.count += 1
| if $n | composite then .composite += 1 else . end;
(select( .count | IN( $points) ) | .n = $n),
if .count == $last then break $out else empty end );
task1(100),
"",
(task2( 1000, 10000, 100000, 1000000 )
| "The \(.count)th arithmetic number is \(.n);",
"there are \(.composite) composite arithmetic numbers up to \(.n).\n")

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@ -0,0 +1,29 @@
using Primes
function isarithmetic(n)
f = [one(n)]
for (p,e) in factor(n)
f = reduce(vcat, [f*p^j for j in 1:e], init=f)
end
return rem(sum(f), length(f)) == 0
end
function arithmetic(n)
i, arr = 1, Int[]
while length(arr) < n
isarithmetic(i) && push!(arr, i)
i += 1
end
return arr
end
a1M = arithmetic(1_000_000)
composites = [!isprime(i) for i in a1M]
println("The first 100 arithmetic numbers are:")
foreach(p -> print(lpad(p[2], 5), p[1] % 20 == 0 ? "\n" : ""), enumerate(a1M[1:100]))
println("\n X Xth in Series Composite")
for n in [1000, 10_000, 100_000, 1_000_000]
println(lpad(n, 9), lpad(a1M[n], 12), lpad(sum(composites[2:n]), 14))
end

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@ -0,0 +1,58 @@
local function factors (n)
local f, i = {1, n}, 2
while true do
local j = n//i -- floor division by Lua 5.3
if j < i then
break
elseif j == i and i * j == n then
table.insert (f, i)
break
elseif i * j == n then
table.insert (f, i)
table.insert (f, j)
end
i = i + 1
end
return f
end
local function sum (f)
local s = 0
for i, value in ipairs (f) do
s = s + value
end
return s
end
local arithmetic_count = 1
local composite_count = 0
local hundr = {1}
for n = 2, 1228663 do
local f = factors (n)
local s = sum (f)
local l = #f
if (s/l)%1 == 0 then
arithmetic_count = arithmetic_count + 1
if l > 2 then
composite_count = composite_count + 1
end
if arithmetic_count <= 100 then
table.insert (hundr, n)
end
if arithmetic_count == 100 then
for i = 0, 9 do
print (table.concat(hundr, ', ', 10*i+1, 10*i+10))
end
elseif arithmetic_count == 1000
or arithmetic_count == 10000
or arithmetic_count == 100000 then
print (arithmetic_count..'th arithmetic number is '..(n))
print ('Number of composite arithmetic numbers <= '..(n)..': '..composite_count)
elseif arithmetic_count == 1000000 then
print (arithmetic_count..'th arithmetic number is '..(n))
print ('Number of composite arithmetic numbers <= '..(n)..': '..composite_count)
return
end
end
end

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@ -0,0 +1,24 @@
set fast !
profiler
form 80, 50
const msg$="The {0::-7}th arithmetic number is {1:-9} up to which {2:-7} are composite."
const f1$="#####,###"
const f2$="###,###"
print "The first 100 arithmetic numbers are:"
C=0&
D=0&: t=0&
mm=1000&
mm1=1000000&
n=1228663 ' 125587 ' 12953 ' 1361
dim L(2 to n)=1, M(2 to n)=1 : c++: Print 1,
for i=2 to n {for j=i to n step i {L(j)+=i:M(j)++}:if L(i) mod M(i) = 0& then {if M(i)>2 then D++
C++:if C<=100& then print i, else i++: goto exit1
}}
exit1:
refresh
for i=i to n {for j=i to n step i {L(j)+=i:M(j)++}:if L(i) mod M(i) = 0& then {if M(i)>2 then D++
C++:if C=mm then ? format$(msg$, c, str$(i,f1$), str$(d,f2$)):refresh:mm*=10&:if mm>mm1 then goto exit2
}}
exit2:
print
print round(timecount/1000, 1);"s"

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@ -0,0 +1,50 @@
ClearAll[ArithmeticNumberQ]
ArithmeticNumberQ[n_Integer] := IntegerQ[Mean[Divisors[n]]]
ArithmeticNumberQ[30]
an = {};
PrintTemporary[Dynamic[{i, Length[an]}]];
Do[
If[ArithmeticNumberQ[i],
AppendTo[an, i];
If[Length[an] >= 100, Break[]]
]
,
{i, 1, \[Infinity]}
];
an
an = {};
Do[
If[ArithmeticNumberQ[i],
AppendTo[an, i];
If[Length[an] >= 1000, Break[]]
]
,
{i, 1, \[Infinity]}
];
a1 = {Length[an], Last[an], Count[CompositeQ[an], True]};
an = {};
Do[
If[ArithmeticNumberQ[i],
AppendTo[an, i];
If[Length[an] >= 10000, Break[]]
]
,
{i, 1, \[Infinity]}
];
a2 = {Length[an], Last[an], Count[CompositeQ[an], True]};
an = {};
Do[
If[ArithmeticNumberQ[i],
AppendTo[an, i];
If[Length[an] >= 100000, Break[]]
]
,
{i, 1, \[Infinity]}
];
a3 = {Length[an], Last[an], Count[CompositeQ[an], True]};
TableForm[{a1, a2, a3}, TableHeadings -> {None, {"X", "Xth in series", "composite"}}]

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@ -0,0 +1,39 @@
import std/strformat
func status(n: int): tuple[isArithmetic, isComposite: bool] =
## Return the status of "n", i.e. whether it is an arithmetic number
## and whether it is composite.
var count = 0
var sum = 0
for d in 1..n:
let q = n div d
if q < d: break
if n mod d == 0:
sum += d
inc count
if q != d:
sum += q
inc count
result = (isArithmetic: sum mod count == 0, isComposite: count > 2)
iterator arithmeticNumbers(): tuple[val: int, isComposite: bool] =
## Yield the successive arithmetic numbers with their composite status.
var n = 1
while true:
let status = n.status
if status.isArithmetic:
yield (n, status.isComposite)
inc n
echo "First 100 arithmetic numbers:"
var arithmeticCount, compositeCount = 0
for (n, isComposite) in arithmeticNumbers():
inc arithmeticCount
inc compositeCount, ord(isComposite)
if arithmeticCount <= 100:
stdout.write &"{n:>3}"
stdout.write if arithmeticCount mod 10 == 0: '\n' else: ' '
elif arithmeticCount in [1_000, 10_000, 100_000, 1_000_000]:
echo &"\n{arithmeticCount}th arithmetic number: {n}"
echo &"Number of composite arithmetic numbers ⩽ {n}: {compositeCount}"
if arithmeticCount == 1_000_000: break

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@ -0,0 +1,84 @@
100H: /* FIND SOME ARITHMETIC NUMBERS: NUMBERS WHOSE AVERAGE DIVISOR IS AN */
/* IS AN INTEGER - I.E. DIVISOR SUM MOD DIVISOR COUNT = 0 */
/* CP/M BDOS SYSTEM CALL, IGNORE THE RETURN VALUE */
BDOS: PROCEDURE( FN, ARG ); DECLARE FN BYTE, ARG ADDRESS; GOTO 5; END;
PR$CHAR: PROCEDURE( C ); DECLARE C BYTE; CALL BDOS( 2, C ); END;
PR$STRING: PROCEDURE( S ); DECLARE S ADDRESS; CALL BDOS( 9, S ); END;
PR$NL: PROCEDURE; CALL PR$STRING( .( 0AH, 0DH, '$' ) ); END;
PR$NUMBER: PROCEDURE( N ); /* PRINTS A NUMBER IN THE MINIMUN FIELD WIDTH */
DECLARE N ADDRESS;
DECLARE V ADDRESS, N$STR ( 6 )BYTE, W BYTE;
V = N;
W = LAST( N$STR );
N$STR( W ) = '$';
N$STR( W := W - 1 ) = '0' + ( V MOD 10 );
DO WHILE( ( V := V / 10 ) > 0 );
N$STR( W := W - 1 ) = '0' + ( V MOD 10 );
END;
CALL PR$STRING( .N$STR( W ) );
END PR$NUMBER;
PR$NUMBER4: PROCEDURE( N ); /* PRINT A NUMBER IN AT LEAST 4 CHARACTERS */
DECLARE N ADDRESS;
IF N < 10 THEN CALL PR$CHAR( ' ' );
IF N < 100 THEN CALL PR$CHAR( ' ' );
IF N < 1000 THEN CALL PR$CHAR( ' ' );
CALL PR$NUMBER( N );
END PR$NUMBER4;
DECLARE ( D$COUNT, D$SUM ) ( 4001 )ADDRESS;
DECLARE ( I, J, D$POS, I$POS, J$POS ) ADDRESS;
/* SHOW THE FIRST 100TH ARITHMETIC NUMBER AND THE 1000TH AND THE 10000TH */
/* ALSO SHOW HOW MANY ARE COMPOSITE */
DECLARE ( DIVISOR$START, DIVISOR$END ) ADDRESS;
DECLARE ( A$COUNT, C$COUNT ) ADDRESS;
A$COUNT, C$COUNT, DIVISOR$START, DIVISOR$END = 0;
I, D$POS = 1;
DO WHILE( I <= 60000 AND A$COUNT < 10000 );
IF I > DIVISOR$END THEN DO;
/* PAST THE END OF THE DIGIT SUMS AND COUNTS - GET THE NEXT BATCH */
DIVISOR$START = DIVISOR$END + 1;
DIVISOR$END = DIVISOR$START + ( LAST( D$COUNT ) ) - 1;
DO I$POS = 1 TO LAST( D$COUNT );
D$COUNT( I$POS ), D$SUM( I$POS ) = 1;
END;
DO I = 2 TO DIVISOR$END;
DO J = I TO DIVISOR$END BY I;
IF J >= DIVISOR$START AND J <= DIVISOR$END THEN DO;
J$POS = J - ( DIVISOR$START - 1 );
D$COUNT( J$POS ) = D$COUNT( J$POS ) + 1;
D$SUM( J$POS ) = D$SUM( J$POS ) + I;
END;
END;
END;
I = DIVISOR$START;
D$POS = 1;
END;
IF D$SUM( D$POS ) MOD D$COUNT( D$POS ) = 0 THEN DO; /* I IS ARITHMETIC */
IF D$COUNT( D$POS ) > 2 THEN DO; /* I IS COMPOSITE */
C$COUNT = C$COUNT + 1;
END;
A$COUNT = A$COUNT + 1;
IF A$COUNT <= 100 THEN DO;
CALL PR$NUMBER4( I );
IF A$COUNT MOD 10 = 0 THEN CALL PR$NL;
END;
ELSE IF A$COUNT = 1000 OR A$COUNT = 10000 THEN DO;
CALL PR$NL;
CALL PR$STRING( .'THE $' );
CALL PR$NUMBER( A$COUNT );
CALL PR$STRING( .'TH ARITHMETIC NUMBER IS: $' );
CALL PR$NUMBER( I );
CALL PR$NL;
CALL PR$STRING( .' THERE ARE $' );
CALL PR$NUMBER( C$COUNT );
CALL PR$STRING( .' COMPOSITE NUMBERS UP TO $' );
CALL PR$NUMBER( I );
CALL PR$NL;
END;
END;
I = I + 1;
D$POS = D$POS + 1;
END;
EOF

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@ -0,0 +1,56 @@
program ArithmeiticNumbers;
procedure ArithmeticNumbers;
var N, ArithCnt, CompCnt, DDiv: longint;
var DivCnt, Sum, Quot, Rem: longint;
begin
N:= 1; ArithCnt:= 0; CompCnt:= 0;
repeat
begin
DDiv:= 1; DivCnt:= 0; Sum:= 0;
while true do
begin
Quot:= N div DDiv;
Rem:=N mod DDiv;
if Quot < DDiv then break;
if (Quot = DDiv) and (Rem = 0) then //N is a square
begin
Sum:= Sum+Quot;
DivCnt:= DivCnt+1;
break;
end;
if Rem = 0 then
begin
Sum:= Sum + DDiv + Quot;
DivCnt:= DivCnt+2;
end;
DDiv:= DDiv+1;
end;
if (Sum mod DivCnt) = 0 then //N is arithmetic
begin
ArithCnt:= ArithCnt+1;
if ArithCnt <= 100 then
begin
Write(N:4);
if (ArithCnt mod 20) = 0 then WriteLn;
end;
if DivCnt > 2 then CompCnt:= CompCnt+1;
case ArithCnt of 1000, 10000, 100000, 1000000:
begin
Writeln;
Write(N, #9 {tab} );
Write(CompCnt);
end;
end;
end;
N:= N+1;
end
until ArithCnt >= 1000000;
WriteLn;
end;
begin
ArithmeticNumbers;
WriteLn('Hit Any Key');
{$IFDEF WINDOWS}ReadLn;{$ENDIF}
end.

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@ -0,0 +1,24 @@
use strict;
use warnings;
use feature 'say';
use List::Util <max sum>;
use ntheory <is_prime divisors>;
use Lingua::EN::Numbers qw(num2en num2en_ordinal);
sub comma { reverse ((reverse shift) =~ s/(.{3})/$1,/gr) =~ s/^,//r }
sub table { my $t = 10 * (my $c = 1 + length max @_); ( sprintf( ('%'.$c.'d')x@_, @_) ) =~ s/.{1,$t}\K/\n/gr }
my @A = 0;
for my $n (1..2E6) {
my @div = divisors $n;
push @A, $n if 0 == sum(@div) % @div;
}
say "The first @{[num2en 100]} arithmetic numbers:";
say table @A[1..100];
for my $x (1E3, 1E4, 1E5, 1E6) {
say "\nThe @{[num2en_ordinal $x]}: " . comma($A[$x]) .
"\nComposite arithmetic numbers ≤ @{[comma $A[$x]]}: " . comma -1 + grep { not is_prime($_) } @A[1..$x];
}

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@ -0,0 +1,27 @@
(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">arithmetic</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">1</span><span style="color: #0000FF;">}</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">composite</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">get_arithmetic</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">nth</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">arithmetic</span><span style="color: #0000FF;">[$]+</span><span style="color: #000000;">1</span>
<span style="color: #008080;">while</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">arithmetic</span><span style="color: #0000FF;">)<</span><span style="color: #000000;">nth</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">divs</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">factors</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">remainder</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">sum</span><span style="color: #0000FF;">(</span><span style="color: #000000;">divs</span><span style="color: #0000FF;">),</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">divs</span><span style="color: #0000FF;">))=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">composite</span> <span style="color: #0000FF;">+=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">divs</span><span style="color: #0000FF;">)></span><span style="color: #000000;">2</span>
<span style="color: #000000;">arithmetic</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">n</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">n</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">1</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">arithmetic</span><span style="color: #0000FF;">[</span><span style="color: #000000;">nth</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #0000FF;">{}</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">get_arithmetic</span><span style="color: #0000FF;">(</span><span style="color: #000000;">100</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;">"The first 100 arithmetic numbers are:\n%s\n"</span><span style="color: #0000FF;">,</span>
<span style="color: #0000FF;">{</span><span style="color: #7060A8;">join_by</span><span style="color: #0000FF;">(</span><span style="color: #000000;">arithmetic</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">10</span><span style="color: #0000FF;">,</span><span style="color: #008000;">" "</span><span style="color: #0000FF;">,</span><span style="color: #000000;">fmt</span><span style="color: #0000FF;">:=</span><span style="color: #008000;">"%3d"</span><span style="color: #0000FF;">)})</span>
<span style="color: #008080;">constant</span> <span style="color: #000000;">fmt</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"The %,dth arithmetic number is %,d up to which %,d are composite.\n"</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">n</span> <span style="color: #008080;">in</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">1e3</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1e4</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1e5</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1e6</span><span style="color: #0000FF;">}</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">nth</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">get_arithmetic</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</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: #000000;">fmt</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">nth</span><span style="color: #0000FF;">,</span><span style="color: #000000;">composite</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<!--

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@ -0,0 +1,30 @@
def factors(n: int):
f = set([1, n])
i = 2
while True:
j = n // i
if j < i:
break
if i * j == n:
f.add(i)
f.add(j)
i += 1
return f
arithmetic_count = 0
composite_count = 0
n = 1
while arithmetic_count <= 1000000:
f = factors(n)
if (sum(f)/len(f)).is_integer():
arithmetic_count += 1
if len(f) > 2:
composite_count += 1
if arithmetic_count <= 100:
print(f'{n:3d} ', end='')
if arithmetic_count % 10 == 0:
print()
if arithmetic_count in (1000, 10000, 100000, 1000000):
print(f'\n{arithmetic_count}th arithmetic number is {n}')
print(f'Number of composite arithmetic numbers <= {n}: {composite_count}')
n += 1

View file

@ -0,0 +1,37 @@
[ factors
0 over witheach +
swap size mod 0 = ] is arithmetic ( n --> b )
[ temp put [] 1
[ over size temp share < while
dup arithmetic if
[ tuck join swap ]
1+
again ]
drop
temp release ] is arithmetics ( n --> [ )
say "First 100 arithmetic numbers:"
cr
100 arithmetics echo
cr cr
say "1000th arithmetic number: "
1000 arithmetics
dup -1 peek
echo cr
say "Composites in first 1000: "
behead drop
0 swap witheach
[ isprime not + ]
echo
cr cr
say "10000th arithmetic number: "
10000 arithmetics
dup -1 peek
echo cr
say "Composites in first 10000: "
behead drop
0 swap witheach
[ isprime not + ]
echo
cr

View file

@ -0,0 +1,11 @@
use Prime::Factor;
use Lingua::EN::Numbers;
my @arithmetic = lazy (1..).hyper.grep: { my @div = .&divisors; @div.sum %% @div }
say "The first { .Int.&cardinal } arithmetic numbers:\n", @arithmetic[^$_].batch(10)».fmt("%{.chars}d").join: "\n" given 1e2;
for 1e3, 1e4, 1e5, 1e6 {
say "\nThe { .Int.&ordinal }: { comma @arithmetic[$_-1] }";
say "Composite arithmetic numbers { comma @arithmetic[$_-1] }: { comma +@arithmetic[^$_].grep({!.is-prime}) - 1 }";
}

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@ -0,0 +1,70 @@
// Author: Gal Zsolt - 2023.02.26.
see "works..." + nl
divisors = []
divSum = 0
limit = 20000
counta = 0
countb = 0
countCompa = 0
countCompb = 0
for n = 1 to limit
num = 0
divSum = 0
for m = 1 to n
if n%m = 0
num++
divSum = divSum + m
ok
next
for x = 1 to n
if divSum/num = x
add(divisors,n)
counta++
countb++
if counta < 1001
if not isPrime(n) and n!=1
countCompa++
ok
ok
if counta = 1000
countNuma = n
ok
if countb < 10001
if not isPrime(n) and n!=1
countCompb++
ok
ok
if countb = 10000
countNumb = n
exit 2
ok
ok
next
next
see "The first 100 arithmetic numbers are:" + nl + nl
row = 0
for n = 1 to 100
row++
see "" + divisors[n] + " "
if row%10=0
see nl
ok
next
see nl
see "1000th arithmetic number is " + countNuma + nl
see "Number of composite arithmetic numbers <= " + countNuma + ":" + countCompa + nl+nl
see "10000th arithmetic number is " + countNumb + nl
see "Number of composite arithmetic numbers <= " + countNumb + ":" + countCompb + nl
see "done..." + nl
func isPrime num
if (num <= 1) return 0 ok
if (num % 2 = 0 and num != 2) return 0 ok
for i = 3 to floor(num / 2) -1 step 2
if (num % i = 0) return 0 ok
next
return 1

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@ -0,0 +1,66 @@
fn divisor_count_and_sum(mut n: u32) -> (u32, u32) {
let mut divisor_count = 1;
let mut divisor_sum = 1;
let mut power = 2;
while (n & 1) == 0 {
divisor_count += 1;
divisor_sum += power;
power <<= 1;
n >>= 1;
}
let mut p = 3;
while p * p <= n {
let mut count = 1;
let mut sum = 1;
power = p;
while n % p == 0 {
count += 1;
sum += power;
power *= p;
n /= p;
}
divisor_count *= count;
divisor_sum *= sum;
p += 2;
}
if n > 1 {
divisor_count *= 2;
divisor_sum *= n + 1;
}
(divisor_count, divisor_sum)
}
fn main() {
let mut arithmetic_count = 0;
let mut composite_count = 0;
let mut n = 1;
while arithmetic_count <= 1000000 {
let (divisor_count, divisor_sum) = divisor_count_and_sum(n);
if divisor_sum % divisor_count != 0 {
n += 1;
continue;
}
arithmetic_count += 1;
if divisor_count > 2 {
composite_count += 1;
}
if arithmetic_count <= 100 {
print!("{:3} ", n);
if arithmetic_count % 10 == 0 {
println!();
}
}
if arithmetic_count == 1000
|| arithmetic_count == 10000
|| arithmetic_count == 100000
|| arithmetic_count == 1000000
{
println!("\n{}th arithmetic number is {}", arithmetic_count, n);
println!(
"Number of composite arithmetic numbers <= {}: {}",
n, composite_count
);
}
n += 1;
}
}

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LET n = 1
DO
LET div = 1
LET divcnt = 0
LET sum = 0
DO
LET quot = n/div
IF quot < div THEN EXIT DO
IF REMAINDER(n, div) = 0 THEN
IF quot = div THEN !n is a square
LET sum = sum+quot
LET divcnt = divcnt+1
EXIT DO
ELSE
LET sum = sum+div+quot
LET divcnt = divcnt+2
END IF
END IF
LET div = div+1
LOOP
IF REMAINDER(sum, divcnt) = 0 THEN !n is arithmetic
LET arithcnt = arithcnt+1
IF arithcnt <= 100 THEN
PRINT USING "####": n;
IF REMAINDER(arithcnt, 20) = 0 THEN PRINT
END IF
IF divcnt > 2 THEN LET compcnt = compcnt+1
SELECT CASE arithcnt
CASE 1000
PRINT
PRINT USING "The #######th arithmetic number is #####,### up to which ###,### are composite.": arithcnt, n, compcnt
CASE 10000, 100000, 1000000
PRINT USING "The #######th arithmetic number is #####,### up to which ###,### are composite.": arithcnt, n, compcnt
CASE ELSE
REM
END SELECT
END IF
LET n = n+1
LOOP UNTIL arithcnt >= 1000000
END

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'arithmetic numbers
'run with CScript
function isarit_compo(i)
cnt=0
sum=0
for j=1 to sqr(i)
if (i mod j)=0 then
k=i\j
if k=j then
cnt=cnt+1:sum=sum+j
else
cnt=cnt+2:sum=sum+j+k
end if
end if
next
avg= sum/cnt
isarit_compo= array((fix(avg)=avg),-(cnt>2))
end function
function rpad(a,n) rpad=right(space(n)&a,n) :end function
dim s1
sub print(s)
s1=s1& rpad(s,4)
if len(s1)=40 then wscript.stdout.writeline s1:s1=""
end sub
'main program
cntr=0
cntcompo=0
i=1
wscript.stdout.writeline "the first 100 arithmetic numbers are:"
do
a=isarit_compo(i)
if a(0) then
cntcompo=cntcompo+a(1)
cntr=cntr+1
if cntr<=100 then print i
if cntr=1000 then wscript.stdout.writeline vbcrlf&"1000th : "&rpad(i,6) & " nr composites " &rpad(cntcompo,6)
if cntr=10000 then wscript.stdout.writeline vbcrlf& "10000th : "&rpad(i,6) & " nr composites " &rpad(cntcompo,6)
if cntr=100000 then wscript.stdout.writeline vbcrlf &"100000th : "&rpad(i,6) & " nr composites " &rpad(cntcompo,6):exit do
end if
i=i+1
loop

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import "./math" for Int, Nums
import "./fmt" for Fmt
import "./sort" for Find
var arithmetic = [1]
var primes = []
var limit = 1e6
var n = 3
while (arithmetic.count < limit) {
var divs = Int.divisors(n)
if (divs.count == 2) {
primes.add(n)
arithmetic.add(n)
} else {
var mean = Nums.mean(divs)
if (mean.isInteger) arithmetic.add(n)
}
n = n + 1
}
System.print("The first 100 arithmetic numbers are:")
Fmt.tprint("$3d", arithmetic[0..99], 10)
for (x in [1e3, 1e4, 1e5, 1e6]) {
var last = arithmetic[x-1]
Fmt.print("\nThe $,dth arithmetic number is: $,d", x, last)
var pcount = Find.nearest(primes, last) + 1
if (!Int.isPrime(last)) pcount = pcount - 1
var comp = x - pcount - 1 // 1 is not composite
Fmt.print("The count of such numbers <= $,d which are composite is $,d.", last, comp)
}

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PROGRAM "ArithmeticNum"
DECLARE FUNCTION Entry ()
FUNCTION Entry ()
N = 1 : ArithCnt = 0 : CompCnt = 0
PRINT "The first 100 arithmetic numbers are:"
DO
Div = 1 : DivCnt = 0 : Sum = 0
DO WHILE 1
Quot = N / Div
IF Quot < Div THEN EXIT DO
IF N MOD Div = 0 THEN
IF Quot = Div THEN 'N is a square
Sum = Sum + Quot
INC DivCnt
EXIT DO
ELSE
Sum = Sum + Div + Quot
DivCnt = DivCnt + 2
END IF
END IF
INC Div
LOOP
IF Sum MOD DivCnt = 0 THEN 'N is arithmetic
INC ArithCnt
IF ArithCnt <= 100 THEN
PRINT FORMAT$("####", N);
IF ArithCnt MOD 20 = 0 THEN PRINT
END IF
IF DivCnt > 2 THEN INC CompCnt
SELECT CASE ArithCnt
CASE 1e3
PRINT "\nThe "; FORMAT$("#######", ArithCnt); "th arithmetic number is"; FORMAT$("####,###", N); " up to which"; FORMAT$("###,###", CompCnt); " are composite."
CASE 1e4, 1e5, 1e6
PRINT "The "; FORMAT$("#######", ArithCnt); "th arithmetic number is"; FORMAT$("####,###", N); " up to which"; FORMAT$("###,###", CompCnt); " are composite."
END SELECT
END IF
INC N
LOOP UNTIL ArithCnt >= 1e6
END FUNCTION
END PROGRAM

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int N, ArithCnt, CompCnt, Div, DivCnt, Sum, Quot;
[Format(4, 0);
N:= 1; ArithCnt:= 0; CompCnt:= 0;
repeat Div:= 1; DivCnt:= 0; Sum:= 0;
loop [Quot:= N/Div;
if Quot < Div then quit;
if Quot = Div and rem(0) = 0 then \N is a square
[Sum:= Sum+Quot; DivCnt:= DivCnt+1; quit];
if rem(0) = 0 then
[Sum:= Sum + Div + Quot;
DivCnt:= DivCnt+2;
];
Div:= Div+1;
];
if rem(Sum/DivCnt) = 0 then \N is arithmetic
[ArithCnt:= ArithCnt+1;
if ArithCnt <= 100 then
[RlOut(0, float(N));
if rem(ArithCnt/20) = 0 then CrLf(0);
];
if DivCnt > 2 then CompCnt:= CompCnt+1;
case ArithCnt of 1000, 10_000, 100_000, 1_000_000:
[CrLf(0);
IntOut(0, N); ChOut(0, 9\tab\);
IntOut(0, CompCnt);
]
other;
];
N:= N+1;
until ArithCnt >= 1_000_000;
]

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@ -0,0 +1,40 @@
// Rosetta Code problem: http://rosettacode.org/wiki/Arithmetic_numbers
// by Jjuanhdez, 06/2022
N = 1 : ArithCnt = 0 : CompCnt = 0
print "The first 100 arithmetic numbers are:"
repeat
Div = 1 : DivCnt = 0 : Sum = 0
while True
Quot = int( N / Div)
if Quot < Div break
if mod(N, Div) = 0 then
if Quot = Div then //N is a square
Sum = Sum + Quot
DivCnt = DivCnt + 1
break
else
Sum = Sum + Div + Quot
DivCnt = DivCnt + 2
end if
end if
Div = Div + 1
end while
if mod(Sum, DivCnt) = 0 then //N is arithmetic
ArithCnt = ArithCnt + 1
if ArithCnt <= 100 then
print N using "####";
if mod(ArithCnt, 20) = 0 print
end if
if DivCnt > 2 CompCnt = CompCnt + 1
switch ArithCnt
case 100
print
case 1000 : case 10000 : case 100000 : case 1e6
print "The ", ArithCnt using "#######", "th arithmetic number is ", N using "####,###", " up to which ", CompCnt using "###,###", " are composite."
end switch
end if
N = N + 1
until ArithCnt >= 1000000