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A288411 Primes of the form k!2+256, where k!2 is the double factorial number (A006852). 1
257, 271, 1201, 10651, 135391, 316234143481, 49988475139107080748861383849035044804037186461213252284425520655249250725695020643146597883951938106998443603515881 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 5 18:48 EDT 2020. Contains 334854 sequences. (Running on oeis4.)