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 A113341 #5 Jun 13 2017 22:50:00 %S A113341 1,3,12,69,560,6059,83215,1399161,28020221,654110586,17494347067, %T A113341 528556017365,17830841841940,665126088764191,27208111182653865, %U A113341 1211942062741823574,58424831462907214924,3031993693950136247986 %N A113341 Column 1 of triangle A113340, also equals column 0 of A113340^3. %o A113341 (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);A[n+2,2] %Y A113341 Cf. A113342 (column 2), A113343 (column 3), A113344 (column 4), A113340, A113360 (=A113340^3). %K A113341 nonn %O A113341 0,2 %A A113341 _Paul D. Hanna_, Nov 08 2005