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 A131919 #4 Mar 05 2022 01:04:52 %S A131919 1,3,3,5,3,5,7,4,4,7,9,5,5,5,9,11,6,6,6,6,11,13,7,7,7,7,7,13,15,8,8,8, %T A131919 8,8,8,15,17,9,9,9,9,9,9,9,17,19,10,10,10,10,10,10,10,10,19 %N A131919 A002024 + A131821 - A000012. %C A131919 Row sums = A028872: (1, 6, 13, 22, 33, 46, ...). %F A131919 A002024 + A131821 - A000012 as infinite lower triangular matrices. %e A131919 First few rows of the triangle: %e A131919 1; %e A131919 3, 3; %e A131919 5, 3, 5; %e A131919 7, 4, 4, 7; %e A131919 9, 5, 5, 5, 9; %e A131919 11, 6, 6, 6, 6, 11; %e A131919 13, 7, 7, 7, 7, 7, 13; %e A131919 ... %Y A131919 Cf. A002024, A131821, A000012, A028872. %K A131919 nonn,tabl %O A131919 0,2 %A A131919 _Gary W. Adamson_, Jul 28 2007