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Primes of the form k!4+256, where k!4 is the quadruple factorial number (A007662).
1

%I #87 Nov 04 2024 16:26:44

%S 257,277,487,1267389841,50491808745015763381,

%T 1008407509171875041482378381,429215532868726286171043772444743140881,

%U 4551830726072842264843919206776501006328381

%N Primes of the form k!4+256, where k!4 is the quadruple factorial number (A007662).

%H Harvey P. Dale, <a href="/A289560/b289560.txt">Table of n, a(n) for n = 1..17</a>

%H Henri& Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n4+256&amp;action=Search">PRP Records.Search for n!4+256.</a>

%H Joe McLean, <a href="http://web.archive.org/web/20091027034731/http://uk.geocities.com/nassarawa%40btinternet.com/probprim2.htm">Interesting Sources of Probable Primes</a>

%H OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>

%t MultiFactorial[n_, k_] := If[n<1, 1, n*MultiFactorial[n-k, k]];

%t Select[Table[MultiFactorial[i, 4] + 256, {i, 0, 100}], PrimeQ[#]&]

%t Select[Table[256+Times@@Range[n,1,-4],{n,200}],PrimeQ] (* _Harvey P. Dale_, Nov 04 2024 *)

%Y Cf. A291349.

%K nonn

%O 1,1

%A _Robert Price_, Sep 02 2017