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 A113390 #5 Jun 13 2017 23:30:45 %S A113390 1,6,66,1091,24891,737061,27110418,1199197442,62240034172, %T A113390 3718021355407,251730371459590,19076604651022143,1601423150451641820, %U A113390 147628858305489901288,14834881996161804192069 %N A113390 Column 1 of triangle A113389, also equals column 0 of A113370^6. %F A113390 Column k of A113389 = column 0 of A113370^(3*k+3) for k>=0. %o A113390 (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^6)[n+1,1] %Y A113390 Cf. A113389, A113378 (column 0), A113391 (column 2), A113370. %K A113390 nonn %O A113390 0,2 %A A113390 _Paul D. Hanna_, Nov 14 2005