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 A130302 #2 Mar 30 2012 17:25:20 %S A130302 1,3,1,6,2,1,10,3,2,1,15,4,3,2,1,21,5,4,3,2,1,28,6,5,4,3,2,1,36,7,6,5, %T A130302 4,3,2,1 %N A130302 A000012 * A130296. %C A130302 Row sums = n^2. A130303 = A130296 * A000012. %F A130302 A000012 * A130296 as infinite lower triangular matrices. Triangular series as the left border; (1,2,3...) in all other columns. %e A130302 First few rows of the triangle are: %e A130302 1; %e A130302 3, 1; %e A130302 6, 2, 1; %e A130302 10, 3, 2, 1; %e A130302 15, 4, 3, 2, 1; %e A130302 21, 5, 4, 3, 2, 1; %e A130302 ... %Y A130302 Cf. A130296, A130303. %K A130302 nonn,tabl %O A130302 1,2 %A A130302 _Gary W. Adamson_, May 20 2007