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 A086502 #5 Feb 21 2013 15:16:35 %S A086502 0,1,18,360,7560,289440,9828000,631169280,46449002880,4526271187200, %T A086502 524461965350400,74044329341875200,12211524764030592000 %N A086502 Number of ordered pairs (a,b) of elements of the symmetric group S_n such that the pair a,b generates a proper subgroup of S_n. %F A086502 a(n) = n!^2 - A071605(n). %Y A086502 Cf. A071605. %K A086502 nonn %O A086502 1,3 %A A086502 Yuval Dekel (dekelyuval(AT)hotmail.com), Sep 09 2003 %E A086502 a(10)-(13) from _Stephen A. Silver_, Feb 21 2013