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 A131876 #14 Apr 18 2024 15:44:08 %S A131876 1,15,7,29,15,13,43,23,21,19,57,31,29,27,25,71,39,37,35,33,31,85,47, %T A131876 45,43,41,39,37,99,55,53,51,49,47,45,43,113,63,61,59,57,55,53,51,49, %U A131876 127,71,69,67,65,63,61,59,57,55,141,79,77,75,73,71,69,67,65,63,61,155,87,85,83,81,79,77,75,73,71,69,67,169,95,93,91,89,87,85,83,81,79,77,75,73,183,103,101,99,97,95,93,91,89,87,85,83,81,79 %N A131876 2*A131873 - 1. %C A131876 Left column = 14n + 1, A131877: (1, 15, 29, 43, 57, 21, ...). %C A131876 Right border = 6n + 1, A016921: (1, 7, 13, 19, ...). %C A131876 Row sums = A131878 (1, 22, 57, 106, 169, ...). %F A131876 2*A131873 - 1 as infinite lower triangular matrices. %e A131876 First few rows of the triangle: %e A131876 1; %e A131876 15, 7; %e A131876 29, 15, 13; %e A131876 43, 23, 21, 19; %e A131876 57, 31, 29, 27, 25; %e A131876 71, 39, 37, 35, 33, 31; %e A131876 85, 47, 45, 43, 41, 39, 37; %e A131876 ... %Y A131876 Cf. A131877, A131878, A131873. %K A131876 nonn,tabl %O A131876 0,2 %A A131876 _Gary W. Adamson_, Jul 22 2007 %E A131876 More terms from _Russ Cox_, Apr 18 2024