Data update

Task/Additive-primes/REXX/additive-primes-2.rexx

@@ -0,0 +1,60 @@
+include Settings
+
+say version; say 'Additive primes'; say
+arg n
+numeric digits 16
+if n = '' then
+   n = -500
+show = (n > 0); n = Abs(n)
+a = AdditivePrimes(n)
+if show then do
+   do i = 1 to a
+      call Charout ,right(addi.additiveprime.i,8)' '
+      if i//10 = 0 then
+         say
+   end
+   say
+end
+say a 'additive primes found below' n
+say Time('e') 'seconds'
+exit
+
+Additiveprimes:
+/* Additive prime numbers */
+procedure expose addi. prim.
+arg x
+/* Init */
+addi. = 0
+/* Fast values */
+if x < 2 then
+   return 0
+if x < 101 then do
+   a = '2 3 5 7 11 23 29 41 43 47 61 67 83 89 999'
+   do n = 1 to Words(a)
+      w = Word(a,n)
+      if w > x then
+         leave
+      addi.additiveprime.n = w
+   end
+   n = n-1; addi.0 = n
+   return n
+end
+/* Get primes */
+p = Primes(x)
+/* Collect additive primes */
+n = 0
+do i = 1 to p
+   q = prim.prime.i; s = 0
+   do j = 1 to Length(q)
+      s = s+Substr(q,j,1)
+   end
+   if IsPrime(s) then do
+      n = n+1; addi.additiveprime.n = q
+   end
+end
+/* Return number of additive primes */
+return n
+
+include Numbers
+include Functions
+include Abend