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 A113342 #5 Jun 13 2017 22:50:01 %S A113342 1,5,35,325,3880,57560,1030751,21763632,531604250,14789895891, %T A113342 462672349092,16100666809097,617634167482824,25916099832677757, %U A113342 1181568927574816310,58194225186901919790,3080529680131892318877 %N A113342 Column 2 of triangle A113340, also equals column 0 of A113340^5. %o A113342 (PARI) a(n)=local(A,B);A=matrix(1,1);A[1,1]=1;for(m=2,n+3,B=matrix(m,m); for(i=1,m, for(j=1,i,if(i<3 || j==i || j>m-1,B[i,j]=1,if(j==1, B[i,1]=1,B[i,j]=(A^(2*j-1))[i-j+1,1]));));A=B);A[n+3,3] %Y A113342 Cf. A113341 (column 1), A113343 (column 3), A113344 (column 4), A113340. %K A113342 nonn %O A113342 0,2 %A A113342 _Paul D. Hanna_, Nov 08 2005