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 A136504 #2 Mar 30 2012 18:37:08
%S A136504 1,0,1,-3,19,-223,5024,-221357,19276981,-3337101203,1151813749025,
%T A136504 -793860037771900,1093434531716214447,-3010922236710802264555,
%U A136504 16578683647583849207539977,-182552322688781602767983229935
%N A136504 Row sums of triangle A136502.
%F A136504 G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n*(1+x)^(2^n).
%o A136504 (PARI) {a(n)=local(M=matrix(n+1,n+1,r,c,binomial(2^(c-1),r-c))); sum(k=0,n,(M^-1)[n+1,k+1])}
%Y A136504 Cf. A136502.
%K A136504 sign
%O A136504 0,4
%A A136504 _Paul D. Hanna_, Jan 01 2008