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 A136503 #2 Mar 30 2012 18:37:08
%S A136503 1,-4,26,-308,6959,-306888,26732904,-4628215312,1597488685120,
%T A136503 -1101039613155676,1516536435306750724,-4175994577753360618608,
%U A136503 22993788379965461938093352,-253190775338116964702467771168
%N A136503 Column 2 of triangle A136502.
%F A136503 G.f.: 1 = Sum_{n>=0} a(n)*x^n*(1+x)^(2^(n+2)).
%o A136503 (PARI) {a(n)=local(M=matrix(n+3,n+3,r,c,binomial(2^(c-1),r-c)));(M^-1)[n+3,3]}
%Y A136503 Cf. A107354 (column 0 of A136502).
%K A136503 sign
%O A136503 0,2
%A A136503 _Paul D. Hanna_, Jan 01 2008