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 A131925 #6 Mar 05 2022 01:45:35 %S A131925 1,5,3,5,7,5,9,7,9,7,9,11,9,11,9,13,11,13,11,13,11,13,15,13,15,13,15, %T A131925 13,17,15,17,15,17,15,17,15,17,19,17,19,17,19,17,19,17 %N A131925 2*A002024 - A000012(signed). %C A131925 Row sums = A077221: (1, 8, 17, 32, 49, 72, 97, ...). %F A131925 2*A002024 - A000012 (signed + - + -, ... by columns). %F A131925 A002024 = (1; 2,2; 3,3,3; ...); A000012(signed) = (1; -1,1; 1,-1,1; ...). %e A131925 First few rows of the triangle: %e A131925 1; %e A131925 5, 3; %e A131925 5, 7, 5; %e A131925 9, 7, 9, 7; %e A131925 9, 11, 9, 11, 9; %e A131925 13, 11, 13, 11, 13, 11; %e A131925 13, 15, 13, 15, 13, 15, 13; %e A131925 .... %Y A131925 Cf. A002024, A000012, A077221. %K A131925 nonn,tabl %O A131925 0,2 %A A131925 _Gary W. Adamson_, Jul 29 2007