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 A096543 #3 Mar 30 2012 18:36:40 %S A096543 0,0,0,5,188,5560,159460,4715480,147031080,4874069760,172184044920, %T A096543 6479888595840,259376627795780,11019372206402560,495710267052627900, %U A096543 23556524839760174080,1179771865401761781520,62133101833103144386560 %N A096543 Formed from a secondary diagonal of triangle A096542 where a(n) = A096542(n,n-2)/3. %Y A096543 Cf. A096542, A096544, A057500. %K A096543 nonn %O A096543 0,4 %A A096543 _Paul D. Hanna_, Jun 25 2004