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 A102088 #4 Mar 30 2012 18:36:44
%S A102088 1,3,10,49,367,3850,52173,868614,17199370,395757887,10396896795,
%T A102088 307511681367,10124396776169,367567456615441,14598938725992903,
%U A102088 630060602243145513,29375322688053255480,1472008290120323375502
%N A102088 Row sums of triangular matrix A102086, which shifts upward to exclude the main diagonal under matrix square.
%o A102088 (PARI) {a(n)=local(A=matrix(2,2),B);A[1,1]=1; for(m=2,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i,B[i,j]=j,if(j==1,B[i,j]=(A^2)[i-1,1], B[i,j]=(A^2)[i-1,j]));));A=B); return(sum(k=0,n,A[n+1,k+1]))}
%Y A102088 Cf. A102086, A102087.
%K A102088 nonn
%O A102088 0,2
%A A102088 _Paul D. Hanna_, Dec 29 2004