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 A113377 #5 Jun 13 2017 23:23:12 %S A113377 1,14,252,5957,179270,6641502,294524076,15285260326,911664081027, %T A113377 61573228385424,4652227417900405,389256081747220268, %U A113377 35759870451009454561,3580704593280285017869,388344720309998846243731 %N A113377 Column 2 of triangle A113374, also equals column 0 of A113381^7. %F A113377 A113374 equals the matrix square of A113370, which has the property: column k of A113370^2 = column 0 of A113381^(3*k+1) for k>=0. %o A113377 (PARI) a(n)=local(A,B);A=Mat(1);for(m=2,n+3,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^2)[n+3,3] %Y A113377 Cf. A113374, A113375 (column 0), A113376 (column 1). %K A113377 nonn %O A113377 0,2 %A A113377 _Paul D. Hanna_, Nov 14 2005