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 A137565 #4 Mar 30 2012 18:59:20
%S A137565 1,8,3072,141557760,1461147874099200,5429466527263925207040000,
%T A137565 10652562037579218110269404217344000000,
%U A137565 15215364593060190936848463156185060517032755200000000
%N A137565 Hankel transform of quadruple factorial numbers A001813.
%F A137565 a(n)=Product{k=0..n-1, (8(k+1)(2k+1))^(n-k)}.
%F A137565 a(n)=8^C(n+1,2)*Product{k=1..n, k!*Product{i=1..k-1, 2i+1}}; a(n)=8^C(n+1,2)*A000178(n)*A057863(n).
%K A137565 easy,nonn
%O A137565 0,2
%A A137565 _Paul Barry_, Jan 26 2008, Apr 25 2008
%E A137565 Edited by _N. J. A. Sloane_, May 14 2008 at the suggestion of R. J. Mathar.