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A288449 Numbers k such that k!6 + 36 is prime, where k!6 is the sextuple factorial number (A085158 ).

%I A288449 #5 Jun 09 2017 19:44:03
%S A288449 1,5,7,13,17,25,29,31,55,77,119,311,373,587,1037,1057,1645,2279,2327,
%T A288449 2531,2893,2917,3293,3799,9139,14131,14405,15041,24923,26563,48743
%N A288449 Numbers k such that k!6 + 36 is prime, where k!6 is the sextuple factorial number (A085158 ).
%C A288449 Corresponding primes are: 37, 41, 43, 127, 971, 43261, 623681, 1340011, 5745471106411, ...
%C A288449 a(32) > 50000.
%C A288449 Terms > 31 correspond to probable primes.
%H A288449 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n!6+36&amp;action=Search">PRP Records. Search for n!6+36.</a>
%H A288449 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 A288449 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>
%e A288449 13!6 + 36 = 13*7*1 + 36 = 127 is prime, so 11 is in the sequence.
%t A288449 MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
%t A288449 Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 6] + 36] &]
%Y A288449 Cf. A007661, A037082, A084438, A123910, A242994.
%K A288449 nonn,more
%O A288449 1,2
%A A288449 _Robert Price_, Jun 09 2017