A289756 - OEIS

%I #6 Jul 12 2017 10:18:02

%S 2,3,5,7,19,47,83,127,359,1847,26879,55439,13366079,188743679,

%T 38761631999,9033331507199,3896394330931199,152349556104345599,

%U 5305528527460761599,57299708096576225279999,160680029832131217407999,383414179456168545484799

%N Primes of the form k!8-1, where k!8 is the octuple factorial number (A114800).

%H Robert Price, <a href="/A289756/b289756.txt">Table of n, a(n) for n = 1..30</a>

%H Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n8-1&amp;action=Search">PRP Records.Search for n!8-1.</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, 8] - 1, {i, 2, 100}], PrimeQ[#]&]

%Y Cf. A204662.

%K nonn

%O 1,1

%A _Robert Price_, Jul 11 2017