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 A130094 #10 Dec 19 2015 07:38:40 %S A130094 1,1,-2,1,0,-2,1,-2,0,1,1,0,0,0,-2,1,-2,-2,0,0,4,1,0,0,0,0,0,-2,1,-2, %T A130094 0,1,0,0,0,0,1,0,-2,0,0,0,0,0,1,1,-2,0,0,-2,0,0,0,0,4 %N A130094 A051731 * an infinite lower triangular matrix with A007427 in the main diagonal. %C A130094 Right border = A007427. Row sums = mu(n), A008683. Nonzero terms by rows are substituted for the factors of n such that row sums = mu(n). Example: for row 6 we map (1, -2, -2, 0, 4), sum = 1, since the factors of 6 are 1, 2, 3 and 6. %F A130094 Inverse Möbius transform of a triangular matrix with A007427 in the main diagonal and the rest zeros. %e A130094 First few rows of the triangle are: %e A130094 1; %e A130094 1, -2; %e A130094 1, 0, -2; %e A130094 1, -2, 0, 1; %e A130094 1, 0, 0, 0, -2; %e A130094 1, -2, -2, 0, 0, 4; %e A130094 1, 0, 0, 0, 0, 0, -2; %e A130094 1, -2, 0, 1, 0, 0, 0, 0; %e A130094 1, 0, -2, 0, 0, 0, 0, 0, 1; %e A130094 ... %Y A130094 Cf. A007427, A008683, A051731. %K A130094 tabl,sign %O A130094 1,3 %A A130094 _Gary W. Adamson_, May 06 2007