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 A130028 #4 Feb 20 2022 01:40:22 %S A130028 1,1,1,3,0,1,3,2,0,1,6,0,1,0,1,4,3,1,1,0,1,10,0,0,0,1,0,1,6,4,1,1,0,1, %T A130028 0,1,12,0,2,0,0,0,1,0,1,8,6,0,1,1,0,0,1,0,1 %N A130028 A129686 * A054523. %C A130028 Row sums = A004277, 1 followed by even terms: (1, 2, 4, 6, 8, 10, ...). %F A130028 A129686 * A054523 as infinite lower triangular matrices, where A129686 = the alternate term operator. %e A130028 First few rows of the triangle: %e A130028 1; %e A130028 1, 1; %e A130028 3, 0, 1; %e A130028 3, 2, 0, 1; %e A130028 6, 0, 1, 0, 1; %e A130028 4, 3, 1, 1, 0, 1; %e A130028 10, 0, 0, 0, 1, 0, 1; %e A130028 6, 4, 1, 1, 0, 1, 0, 1; %e A130028 ... %Y A130028 Cf. A129686, A054523, A004277. %K A130028 nonn,tabl %O A130028 1,4 %A A130028 _Gary W. Adamson_, May 02 2007