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 A124528 #3 Mar 30 2012 18:37:01
%S A124528 1,1,3,8,26,94,377,1639,7623,38034,199338,1111816,6442481,39478219,
%T A124528 249507483,1659172454,11321526022,80944313164,591617080305,
%U A124528 4514822914133,35120998653271,284407875530728,2342407874087454
%N A124528 a(n) = Sum_{k=0..n} 2^k*A124526(n,k) for n>=0.
%o A124528 (PARI) {a(n)=sum(k=0,n\2,2^k*(n\2)!*((n+1)\2)!*polcoeff(polcoeff(exp((1+y)*(exp(x+x*O(x^n))-1)),n\2),k) *polcoeff(polcoeff(exp((1+y)*(exp(x+x*O(x^n))-1)),(n+1)\2),k))}
%Y A124528 Cf. A124526, A124527, A124529.
%K A124528 nonn
%O A124528 0,3
%A A124528 _Paul D. Hanna_, Nov 08 2006