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 A113388 #5 Jun 13 2017 23:30:49 %S A113388 1,6,48,605,11196,280440,8981460,353283128,16567072675,905357065354, %T A113388 56632746126107,3997082539456084,314584709388906568, %U A113388 27340439653453247728,2602372304420672868499,269388182085308601450047 %N A113388 Column 0 of triangle A113387, also equals column 0 of A113389^2. %F A113388 A113387 equals the matrix cube of A113381, which has the property: column k of A113381^3 = column 0 of A113389^(3*k+2) for k>=0. %o A113388 (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); (matrix(#A,#A,r,c,if(r>=c,(A^(3*c-1))[r-c+1,1]))^3)[n+1,1] %Y A113388 Cf. A113381, A113387, A113389. %K A113388 nonn %O A113388 0,2 %A A113388 _Paul D. Hanna_, Nov 14 2005