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 A132694 #2 Mar 30 2012 18:37:04
%S A132694 1,1,-4,35,-455,7735,-161336,3973212,-112587210,3603324835,
%T A132694 -128433778935,5042279130343,-216113991649920,10038333251577820,
%U A132694 -502213976534135280,26920671954736535620,-1539171664433009622090,93492751831594011076131,-6012423991038631627857900
%N A132694 Column 3 of triangle A132690.
%C A132694 Triangle T=A132690 is generated from negative powers of itself such that row n+1 of T = row n of T^(-n) with appended '1' for n>=0 with T(0,0)=1.
%o A132694 (PARI) {a(n)=local(A=Mat(1), B); for(m=1, n+4, 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+4,4]))}
%Y A132694 Cf. A132690; A132691, A132692, A132693.
%K A132694 sign
%O A132694 0,3
%A A132694 _Paul D. Hanna_, Aug 25 2007