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 A136469 #2 Mar 30 2012 18:37:08
%S A136469 1,4,36,972,82692,22668224,20480767016,62399482333360,
%T A136469 654732295896172624,24092174555680443592896,
%U A136469 3156168229958886081384337440,1490220874303979634022445823087616
%N A136469 Column 2 of triangle A136467 (scaled): a(n) = A136467(n+2,2)/4^n.
%o A136469 (PARI) {a(n)=local(M=matrix(n+3,n+3,r,c,binomial(r*2^(c-2),c-1)),P); P=matrix(n+3,n+3,r,c,binomial((r+1)*2^(c-2),c-1));(P~*M~^-1)[n+3,3]/4^n}
%Y A136469 Cf. A136467; A136468.
%K A136469 nonn
%O A136469 0,2
%A A136469 _Paul D. Hanna_, Dec 31 2007