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A289701 Numbers k such that k!6 - 48 is prime, where k!6 is the sextuple factorial number (A085158).

%I A289701 #13 Nov 29 2018 16:21:19
%S A289701 11,13,17,25,35,41,73,77,89,113,115,121,125,137,155,169,287,521,709,
%T A289701 721,1999,2333,3029,4067,6343,6773,11065,14095,29969,36181,50155,
%U A289701 60973,84731,88769
%N A289701 Numbers k such that k!6 - 48 is prime, where k!6 is the sextuple factorial number (A085158).
%C A289701 Corresponding primes are: 7, 43, 887, 43177, 21827527, 894930527, 1714167050058087577, ...
%C A289701 a(35) > 10^5.
%C A289701 Terms > 41 correspond to probable primes.
%H A289701 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n!6-48&amp;action=Search">PRP Records. Search for n!6-48.</a>
%H A289701 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 A289701 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a>
%e A289701 13!6 - 48 = 13*7*1 - 48 = 43 is prime, so 13 is in the sequence.
%t A289701 MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
%t A289701 Select[Range[11, 50000], PrimeQ[MultiFactorial[#, 6] - 48] &]
%Y A289701 Cf. A007661, A037082, A084438, A123910, A242994.
%K A289701 nonn,more
%O A289701 1,1
%A A289701 _Robert Price_, Jul 09 2017
%E A289701 a(31)-a(34) from _Robert Price_, Aug 04 2018