A343770 Numbers k such that 2*k+(A187129(k) mod A185297(k)) is prime.

11, 20, 22, 31, 32, 49, 64, 103, 110, 173, 293, 454, 496, 505, 589, 673, 701, 772, 784, 821, 884, 979, 1039, 1292, 1711, 1988, 2236, 2266, 2662, 2701, 4804, 6772, 8641, 8948, 13504, 23867, 40241

Offset: 1

Author

J. M. Bergot and Robert Israel, Apr 28 2021

Keywords

• nonn
• more

Examples

			a(5) = 32 is a term because A187129(32) = 261,
A185297(32) = 59, and 2*32+(261 mod 59) = 89 is prime.
		

Crossrefs

Cf. A185297, A187129.

Programs

Maple

g:= proc(n) local i,L,x,y;
  L:= select(t -> isprime(t) and isprime(2*n-t), [2,seq(i,i=3..n,2)]);
  x:= convert(L,`+`);
  y:= nops(L)*2*n - x;
  y mod x
end proc:
select(n -> isprime(2*n+g(n)), [$2..10000]); # Robert Israel, Apr 29 2021

PARI

apq(n) = my(s=0, t=0); forprime(p=1, n, if (isprime(2*n-p), s += p; t+= 2*n-p)); t % s;
isok(k) = isprime(2*k + apq(k)); \\ Michel Marcus, Apr 29 2021