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 A134540 #9 Mar 26 2022 10:15:23 %S A134540 1,0,1,0,1,1,0,0,1,1,0,1,1,1,1,0,-1,0,1,1,1,0,1,1,1,1,1,1,0,0,0,0,1,1, %T A134540 1,1,0,0,0,1,1,1,1,1,1,0,-1,0,0,0,1,1,1,1,1 %N A134540 A054525 * A000012. %C A134540 Row sums = phi(n), A000010: (1, 1, 2, 2, 4, 2, 6, 4, 6, 4, ...). %F A134540 A054525 * A000012 as infinite lower triangular matrices. %F A134540 Triangle read by rows, partial sums of A054525 (the Mobius transform) terms starting from the right. %e A134540 First few rows of the triangle: %e A134540 1; %e A134540 0, 1; %e A134540 0, 1, 1; %e A134540 0, 0, 1, 1; %e A134540 0, 1, 1, 1, 1; %e A134540 0, -1, 0, 1, 1, 1; %e A134540 0, 1, 1, 1, 1, 1, 1; %e A134540 0, 0, 0, 0, 1, 1, 1, 1; %e A134540 0, 0, 0, 1, 1, 1, 1, 1, 1; %e A134540 0, -1, 0, 0, 0, 1, 1, 1, 1, 1; %e A134540 ... %Y A134540 Cf. A054525. %K A134540 tabl,sign,more %O A134540 1,1 %A A134540 _Gary W. Adamson_, Oct 31 2007