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

1,1

Links

Table of n, a(n) for n=1..37.

Example

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

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

Prog

(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

Crossrefs

Cf. A185297, A187129.

Sequence in context: A279431 A230541 A053715 * A250203 A339307 A038581

Adjacent sequences: A343767 A343768 A343769 * A343771 A343772 A343773

Keyword

nonn,more

Author

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

Status

approved