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 A113091 #7 Jun 20 2022 04:14:31
%S A113091 1,12,255,11326,1136709,272246616,162043308555,246976754748242,
%T A113091 985451332639242321,10465989453804481920460,
%U A113091 299684548041297413533699479,23373481327888949572209959486022,5007060652963472122780384849366677469
%N A113091 Column 1 of triangle A113090.
%o A113091 (PARI) {a(n)=local(M=matrix(n+1,n+1));for(r=1,n+1, for(c=1,r, M[r,c]=if(r==c,1,if(c>1,(M^3)[r-1,c-1])+(M^3)[r-1,c]))); return(if(n<1,0,(M^3)[n+1,2]))}
%Y A113091 Cf. A113090.
%K A113091 nonn
%O A113091 1,2
%A A113091 _Paul D. Hanna_, Oct 14 2005