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 A133727 #5 Mar 23 2022 01:07:10 %S A133727 1,1,2,1,0,5,1,2,0,7,1,0,0,0,14,1,2,5,0,0,13,1,0,0,0,0,0,27,1,2,0,7,0, %T A133727 0,0,26,1,0,5,0,0,0,0,0,39,1,2,0,0,14,0,0,0,0,38 %N A133727 A051731 * A007438 as a diagonalized matrix. %C A133727 Row sums = the triangular numbers: (1, 3, 6, 10, 15, ...). %C A133727 Right diagonal = A007438. %F A133727 Inverse Mobius transform of A007438 as a diagonalized matrix; i.e., A051731 * (1; 0,2 0,0,5; 0,0,0,7; ...) where A007438 = (1, 2, 5, 7, 14, 13, 27, ...), the Mobius transform of the triangular numbers. %e A133727 First few rows of the triangle: %e A133727 1; %e A133727 1, 2; %e A133727 1, 0, 5; %e A133727 1, 2, 0, 7; %e A133727 1, 0, 0, 0, 14; %e A133727 1, 2, 5, 0, 0, 13; %e A133727 1, 0, 0, 0, 0, 0, 27; %e A133727 ... %Y A133727 Cf. A007438, A051731. %K A133727 nonn,tabl %O A133727 1,3 %A A133727 _Gary W. Adamson_, Sep 21 2007