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 A125805 #5 Jun 14 2017 00:16:07 %S A125805 1,2,4,10,41,361,7741,417212,57581062,20688363559,19625079296963, %T A125805 49742424992663959,340292157995636104240,6337196928437059669994069, %U A125805 323627960380394115802942263514,45610724032832026072070666274435391 %N A125805 Antidiagonal sums of table A125800. %C A125805 Table A125800 is related to partitions into powers of 3; column k of A125800 equals row sums of matrix power A078122^k, where triangle A078122 shifts left one column under matrix cube. %o A125805 (PARI) a(n)=local(q=3,A=Mat(1), B); for(m=1, n+1, B=matrix(m, m); for(i=1, m, for(j=1, i, if(j==i || j==1, B[i, j]=1, B[i, j]=(A^q)[i-1, j-1]); )); A=B); return(sum(c=0,n,(A^(c+1))[n-c+1,1])) %Y A125805 Cf. A125800, A078122; columns: A078125, A078124, A125801, A125802, A125803; A125804 (diagonal). %K A125805 nonn %O A125805 0,2 %A A125805 _Paul D. Hanna_, Dec 10 2006