A340618 Numbers k such that A316650(k) is prime.

13, 15, 19, 23, 31, 33, 35, 37, 43, 47, 51, 52, 59, 73, 78, 85, 93, 94, 97, 99, 105, 106, 109, 113, 115, 119, 127, 129, 139, 141, 149, 159, 163, 165, 168, 169, 179, 181, 189, 199, 211, 213, 218, 231, 232, 237, 245, 251, 256, 258, 259, 271, 273, 274, 275, 294, 301, 303, 304, 307, 339, 344, 347, 348

Offset: 1

Author

J. M. Bergot and Robert Israel, Jan 15 2021

Keywords

• nonn
• base

Examples

			a(4) = 23 is a term because A316650(23) = 43 is prime.
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A316650.

Programs

Maple

f:= proc(n) local a,b,c;
  c:= convert(convert(n,base,10),`+`);
  a:= floor(n/c);
  b:= n mod c;
  10^(1+ilog10(b))*a+b;
end proc:
select(n -> isprime(f(n)), [$1..100]);