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 A113346 #5 Jun 13 2017 22:50:23 %S A113346 1,2,5,19,113,966,10958,156700,2727794,56306696,1350043965, %T A113346 36979531549,1141573025172,39272377323693,1491452150268436, %U A113346 62027842189908231,2805631215820328992,137199563717151509077,7215932308408758314447 %N A113346 Column 0 of triangle A113345, also equals column 0 of A113350. %C A113346 A113345 is the matrix square of A113340. %o A113346 (PARI) a(n)=local(A,B);A=matrix(1,1);A[1,1]=1;for(m=2,n+1,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^2)[n+1,1] %Y A113346 Cf. A113340, A113345, A113347 (column 1), A113348 (column 2), A113349 (column 3); A113350. %K A113346 nonn %O A113346 0,2 %A A113346 _Paul D. Hanna_, Nov 08 2005