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 A131248 #4 Feb 18 2022 22:36:59 %S A131248 1,1,1,1,3,1,1,3,5,1,1,3,7,7,1,1,3,7,13,9,1,1,3,7,15,21,11,1,1,3,7,15, %T A131248 29,31,13,1,1,3,7,15,31,51,43,15,1,1,3,7,15,31,61,83,57,17,1 %N A131248 2*A004070 - A000012. %C A131248 Row sums = A104161: (1, 2, 5, 10, 19, 34, 59, ...). %F A131248 2*A004070 - A000012 as infinite lower triangular matrices. Reversal triangle of A131247, read by rows. %e A131248 First few rows of the triangle: %e A131248 1; %e A131248 1, 1; %e A131248 1, 3, 1; %e A131248 1, 3, 5, 1; %e A131248 1, 3, 7, 7, 1; %e A131248 1, 3, 7, 13, 9, 1; %e A131248 1, 3, 7, 15, 21, 11, 1; %e A131248 1, 3, 7, 15, 29, 31, 13, 1; %e A131248 ... %Y A131248 Cf. A004070, A000012, A104161, A131247. %K A131248 nonn,tabl %O A131248 0,5 %A A131248 _Gary W. Adamson_, Jun 23 2007