A145315 Numbers k for which the set {30*k-13, 30*k-11, 30*k-7, 30*k-1, 30*k+1, 30*k+7, 30*k+11, 30*k+13} forms a symmetrical prime octuplet.

1, 43, 3772, 86022, 691263, 1940280, 2445785, 2539018, 3355288, 4492167, 4598112, 5517709, 5731956, 7466941, 8409234, 9817872, 10324700, 10390862, 12138468, 13631232, 17181592, 17382707, 17609073, 20633677, 20897582, 22760333, 23389302, 32968102, 36051016, 37215088

Offset: 1

Author

Andrey V. Kulsha, Oct 07 2008

Keywords

• nonn

Comments

a(n) is always +/- 1 (mod 7).

Crossrefs

Cf. A022012.

Programs

Mathematica

spoQ[n_]:=Module[{c=30n},And@@PrimeQ[{c-13,c-11,c-7,c-1,c+1,c+7,c+11, c+13}]]; Select[Range[23000000],spoQ] (* Harvey P. Dale, Oct 10 2011 *)

Formula

a(n) = (A022012(n) + 13)/30. - Hugo Pfoertner, Nov 08 2022