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 A113391 #5 Jun 13 2017 23:30:43 %S A113391 1,9,153,3621,110637,4176549,188802141,9981491997,605817292893, %T A113391 41590997891929,3190816992548889,270817573670371995, %U A113391 25214094974302894695,2556615042094813435491,280570514270855698070535 %N A113391 Column 2 of triangle A113389, also equals column 0 of A113370^9. %F A113391 Column k of A113389 = column 0 of A113370^(3*k+3) for k>=0. %o A113391 (PARI) a(n)=local(A,B);A=Mat(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^(3*j-2))[i-j+1,1]));));A=B);(A^9)[n+1,1] %Y A113391 Cf. A113389, A113378 (column 0), A113390 (column 1), A113370. %K A113391 nonn %O A113391 0,2 %A A113391 _Paul D. Hanna_, Nov 14 2005