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 A113380 #5 Jun 13 2017 23:23:08 %S A113380 1,12,168,3190,80136,2553162,99579994,4624245724,250138459808, %T A113380 15488221792442,1082305443525010,84364431201000877, %U A113380 7264439969560330768,685338322012632405151,70341947440289270101707 %N A113380 Column 1 of triangle A113378, also equals column 0 of A113389^4. %F A113380 A113378 equals the matrix cube of A113370, which has the property: column k of A113370^3 = column 0 of A113389^(3*k+1) for k>=0. %o A113380 (PARI) a(n)=local(A,B);A=Mat(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^(3*j-2))[i-j+1,1]));));A=B);(A^3)[n+2,2] %Y A113380 Cf. A113378, A113370, A113389, A113379 (column 0). %K A113380 nonn %O A113380 0,2 %A A113380 _Paul D. Hanna_, Nov 14 2005