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 A131897 #6 Mar 04 2022 02:05:55 %S A131897 1,3,2,6,2,3,11,4,2,4,20,8,4,2,5,37,16,8,4,2,6,70,32,16,8,4,2,7,135, %T A131897 64,32,16,8,4,2,8,264,128,64,32,16,8,4,2,9,521,256,128,64,32,16,8,4,2, %U A131897 10 %N A131897 A130321 + A131821 - A000012. %C A131897 Left column = A006127: (1, 3, 6, 11, 20, 37, ...). %C A131897 Row sums = A131898: (1, 5, 11, 21, 39, 73, ...). %F A131897 A131321 + A131821 - A000012 as infinite lower triangular matrices. %e A131897 First few rows of the triangle: %e A131897 1; %e A131897 3, 2; %e A131897 6, 2, 3; %e A131897 11, 4, 2, 4; %e A131897 20, 8, 4, 2, 5; %e A131897 37, 16, 8, 4, 2, 6; %e A131897 70, 32, 16, 8, 4, 2, 7; %e A131897 ... %Y A131897 Cf. A130321, A131821, A006127, A131898. %K A131897 nonn,tabl %O A131897 0,2 %A A131897 _Gary W. Adamson_, Jul 25 2007