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 A131247 #4 Feb 18 2022 22:36:34 %S A131247 1,1,1,1,3,1,1,5,3,1,1,7,7,3,1,1,9,13,7,3,1,1,11,21,15,7,3,1,1,13,31, %T A131247 29,15,7,3,1,1,15,43,51,31,15,7,3,1,1,17,57,83,61,31,15,7,3,1 %N A131247 2*A052509 - A000012. %C A131247 Row sums = A104161 starting (1, 2, 5, 10, 19, 34, 59, ...). Reversal, A131248 is generated from 2*A004070 - A000012. %F A131247 2*A052509 - A000012, where A000012 = (1; 1,1; 1,1,1; ...). %e A131247 First few rows of the triangle: %e A131247 1; %e A131247 1, 1; %e A131247 1, 3, 1; %e A131247 1, 5, 3, 1; %e A131247 1, 7, 7, 3, 1; %e A131247 1, 9, 13, 7, 3, 1; %e A131247 1, 11, 21, 15, 7, 3, 1; %e A131247 ... %Y A131247 Cf. A052509, A104161, A004070, A131248. %K A131247 nonn,tabl %O A131247 0,5 %A A131247 _Gary W. Adamson_, Jun 23 2007