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A288154 Numbers k such that k!6 + 9 is prime, where k!6 is the sextuple factorial number (A085158 ).

%I A288154 #6 Jun 05 2017 23:09:22
%S A288154 2,4,14,28,34,46,50,52,86,100,106,140,166,170,208,242,338,344,412,
%T A288154 1360,2024,2948,3650,5608,5744,7618,8410,8834,11872,12514,13636,18742,
%U A288154 20846,29750,31312
%N A288154 Numbers k such that k!6 + 9 is prime, where k!6 is the sextuple factorial number (A085158 ).
%C A288154 Corresponding primes are: 11, 13, 233, 394249, 13404169, 24663654409, 311607296009, ...
%C A288154 a(36) > 50000.
%C A288154 Terms > 50 correspond to probable primes.
%H A288154 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n!6+9&amp;action=Search">PRP Records. Search for n!6+9.</a>
%H A288154 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 A288154 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>
%e A288154 14!6 + 9 = 14*8*2 + 9 = 233 is prime, so 14 is in the sequence.
%t A288154 MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
%t A288154 Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 9] &]
%Y A288154 Cf. A007661, A037082, A084438, A123910, A242994.
%K A288154 nonn,more
%O A288154 1,1
%A A288154 _Robert Price_, Jun 05 2017