This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A289689 #12 Nov 29 2018 16:19:29 %S A289689 9,15,17,65,129,135,209,225,327,357,423,1061,1143,3629,4937,6713, %T A289689 33123,79185,88323,89933 %N A289689 Numbers k such that k!6 - 16 is prime, where k!6 is the sextuple factorial number (A085158). %C A289689 Corresponding primes are: 11, 389, 919, 8549258359016359, 17694587964658118355578965371540271859, ... %C A289689 a(21) > 10^5. %C A289689 Terms > 17 correspond to probable primes. %H A289689 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n!6-16&action=Search">PRP Records. Search for n!6-16.</a> %H A289689 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 A289689 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a> %e A289689 17!6 - 16 = 17*11*5 - 16 = 919 is prime, so 17 is in the sequence. %t A289689 MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; %t A289689 Select[Range[6, 50000], PrimeQ[MultiFactorial[#, 6] - 16] &] %Y A289689 Cf. A007661, A037082, A084438, A123910, A242994. %K A289689 nonn,more %O A289689 1,1 %A A289689 _Robert Price_, Jul 09 2017 %E A289689 a(18)-a(20) from _Robert Price_, Aug 03 2018