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 A130307 #4 Feb 20 2022 14:52:56 %S A130307 1,3,1,4,1,1,7,2,1,1,6,1,1,1,1,12,3,2,1,1,1,8,1,1,1,1,1,1,15,3,2,2,1, %T A130307 1,1,1,13,2,2,1,1,1,1,1,1,18,3,2,2,2,1,1,1,1,1 %N A130307 A051731 * A130296. %C A130307 Row sums = A129235, (1, 4, 6, 11, 10, 20, 14, ...). %C A130307 Left column = sigma(n), A000203. %F A130307 Inverse Moebius transform of A130296. %e A130307 First few rows of the triangle: %e A130307 1; %e A130307 3, 1; %e A130307 4, 1, 1; %e A130307 7, 2, 1, 1; %e A130307 6, 1, 1, 1, 1; %e A130307 12, 3, 2, 1, 1, 1; %e A130307 8, 1, 1, 1, 1, 1, 1; %e A130307 ... %Y A130307 Cf. A130296, A051731, A129235, A000203. %K A130307 nonn %O A130307 0,2 %A A130307 _Gary W. Adamson_, May 20 2007