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 A130027 #5 Feb 20 2022 01:39:59 %S A130027 1,1,1,2,0,1,1,2,0,1,4,0,0,0,1,-2,4,3,0,0,1,6,0,0,0,0,0,1,1,2,0,4,0,0, %T A130027 0,1,2,0,6,0,0,0,0,0,1,-4,8,0,0,5,0,0,0,0,1 %N A130027 A130026 * A054525. %C A130027 Row sums = (1, 2, 3, ...). Left column = signed version of A070777. %F A130027 A130026 * A054525 as infinite lower triangular matrices. %e A130027 First few rows of the triangle: %e A130027 1; %e A130027 1, 1; %e A130027 2, 0, 1; %e A130027 1, 2, 0, 1; %e A130027 4, 0, 0, 0, 1; %e A130027 -2, 4, 3, 0, 0, 1; %e A130027 6, 0, 0, 0, 0, 0, 1; %e A130027 1, 2, 0, 4, 0, 0, 0, 1; %e A130027 ... %Y A130027 Cf. A130027, A070777. %K A130027 tabl,sign %O A130027 1,4 %A A130027 _Gary W. Adamson_, May 02 2007