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 A113357 #5 Jun 13 2017 23:05:05 %S A113357 1,8,68,712,9270,147174,2786270,61662544,1568627031,45226595865, %T A113357 1460494997316,52298603045920,2059014449303471,88476000281671109, %U A113357 4123177399591735062,207239886694280045429,11179817701706220363653 %N A113357 Column 1 of triangle A113355, also equals column 0 of A113355^2. %C A113357 A113355 equals the matrix square of A113350, where column 1 of A113350^2 = column 0 of A113350^4. %o A113357 (PARI) a(n)=local(A,B);A=matrix(1,1);A[1,1]=1;for(m=2,n+2,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); (matrix(#A,#A,r,c,if(r>=c,(A^(2*c))[r-c+1,1]))^2)[n+2,2] %Y A113357 Cf. A113340, A113350, A113355, A113356 (column 0), A113358 (column 2), A113359 (column 3). %K A113357 nonn %O A113357 0,2 %A A113357 _Paul D. Hanna_, Nov 08 2005