A288411 Primes of the form k!2+256, where k!2 is the double factorial number (A006852).

257, 271, 1201, 10651, 135391, 316234143481, 49988475139107080748861383849035044804037186461213252284425520655249250725695020643146597883951938106998443603515881

Offset

1,1

Comments

The next term has 174 digits. - Harvey P. Dale, Mar 09 2018

Links

Robert Price, Table of n, a(n) for n = 1..8

Henri& Renaud Lifchitz, PRP Records.Search for n!2+256.

Joe McLean, Interesting Sources of Probable Primes

OpenPFGW Project, Primality Tester

Mathematica

MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];
Select[Table[MultiFactorial[i, 2] + 256, {i, 0, 100}], PrimeQ[#]&]
Select[Range[200]!!+256, PrimeQ] (* Harvey P. Dale, Mar 09 2018 *)

Crossrefs

Cf. A076195.

Sequence in context: A253149 A139653 A273551 * A060879 A062382 A289560

Adjacent sequences: A288408 A288409 A288410 * A288412 A288413 A288414

Keyword

nonn

Author

Robert Price, Jun 08 2017

Status

approved