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 A113128 #2 Mar 30 2012 18:59:12 %S A113128 1,3,2,3,6,3,1,6,9,4,0,2,9,12,5,0,0,3,12,15,6,0,0,0,4,15,18,7,0,0,0,0, %T A113128 5,18,21,8,0,0,0,0,0,6,21,24,9,0,0,0,0,0,0,7,24,27,10,0,0,0,0,0,0,0,8, %U A113128 27,30,11,0,0,0,0,0,0,0,0,9,30,33,12,0,0,0,0,0,0,0,0,0,10,33,36,13,0,0,0,0 %N A113128 A simple 4-diagonal matrix based on (1+x)^3. %C A113128 Row sums are A086570. Diagonal sums are the odd numbers A005408. %F A113128 Number triangle where column k has g.f. (1+x)^3*(k+1)x^k. %e A113128 Triangle begins %e A113128 1; %e A113128 3, 2; %e A113128 3, 6, 3; %e A113128 1, 6, 9, 4; %e A113128 0, 2, 9, 12, 5; %e A113128 0, 0, 3, 12, 15, 6; %e A113128 0, 0, 0, 4, 15, 18, 7; %e A113128 0, 0, 0, 0, 5, 18, 21, 8; %K A113128 easy,nonn,tabl %O A113128 0,2 %A A113128 _Paul Barry_, Oct 14 2005