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 A132691 #2 Mar 30 2012 18:37:04
%S A132691 1,1,-1,5,-43,527,-8396,164672,-3835910,103464895,-3170985454,
%T A132691 108828369497,-4134333957073,172223139437835,-7805591781504739,
%U A132691 382374360671653989,-20132511625986242785,1133765691312312723347,-68002260363248096548050
%N A132691 Column 0 of triangle A132690.
%o A132691 (PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i, B[i, j]=1, B[i, j]=(A^(-(i-2)))[i-1, j]); )); A=B); return( ((A)[n+1,1]))}
%Y A132691 Cf. A132690; A132692, A132693, A132694.
%K A132691 sign
%O A132691 0,4
%A A132691 _Paul D. Hanna_, Aug 25 2007