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 A289687 #18 Nov 29 2018 16:22:01 %S A289687 8,10,16,22,26,46,52,56,70,74,286,302,308,484,698,1100,1226,1528,2486, %T A289687 3796,4256,8524,10688,19424,22226,49346,53746,64178,84304 %N A289687 Numbers k such that k!6 - 9 is prime, where k!6 is the sextuple factorial number (A085158). %C A289687 Corresponding primes are: 7, 31, 631, 14071, 116471, 24663654391, 1282510028791, ... %C A289687 a(30) > 10^5. %C A289687 Terms > 46 correspond to probable primes. %H A289687 Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=n!6-9&action=Search">PRP Records. Search for n!6-9.</a> %H A289687 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 A289687 OpenPFGW Project, <a href="http://sourceforge.net/projects/openpfgw/">Primality Tester</a> %e A289687 16!6 - 9 = 16*10*4 - 8 = 631 is prime, so 16 is in the sequence. %t A289687 MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; %t A289687 Select[Range[8, 50000], PrimeQ[MultiFactorial[#, 6] - 9] &] %Y A289687 Cf. A007661, A037082, A084438, A123910, A242994. %K A289687 nonn,more %O A289687 1,1 %A A289687 _Robert Price_, Jul 09 2017 %E A289687 a(27)-a(29) from _Robert Price_, Aug 03 2018