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 A081713 #9 Nov 15 2019 16:04:37 %S A081713 4,5,20,92,106,266,308,343,583,597,903,1021,1239,1314,2458,6160,9627, %T A081713 10649 %N A081713 n! - n# - 1 is prime, where n# is the primorial function. %C A081713 Some of the larger entries may only correspond to probable primes. %H A081713 Mike Oakes, <a href="http://groups.yahoo.com/group/primenumbers/message/12028">Primo-factorials</a>. %H A081713 Mike Oakes, <a href="/A081710/a081710.txt">Primo-factorials</a>, message 12028 in primenumbers Yahoo group, Apr 3, 2003. [Cached copy] %H A081713 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>. %e A081713 a(1)=4 because 4!-4#-1=17 is prime %Y A081713 Cf. A081710, A081711, A081712. %K A081713 nonn,more,hard %O A081713 1,1 %A A081713 _Mike Oakes_, Apr 04 2003 %E A081713 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008