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 A127572 #6 Mar 30 2012 17:35:17 %S A127572 1,2,3,3,0,4,4,6,0,7,5,0,0,0,6,6,9,8,0,0,12,7,0,0,0,0,0,8,8,12,0,14,0, %T A127572 0,0,15,9,0,12,0,0,0,0,0,13,10,15,0,0,12,0,0,0,0,18 %N A127572 Triangle, T(n,k) = sigma(k) * n/k if k|n, T(n,k) = 0 otherwise. %F A127572 A126988 * M, where M = an infinite matrix with sigma(n) in the main diagonal and the rest zeros. %e A127572 First few rows of the triangle are: %e A127572 1; %e A127572 2, 3; %e A127572 3, 0, 4; %e A127572 4, 6, 0, 7; %e A127572 5, 0, 0, 0, 6; %e A127572 6, 9, 8, 0, 0, 12; %e A127572 ... %Y A127572 Main diagonal = sigma(n), A000203; row sums = A060640. %Y A127572 Cf. A126988. %K A127572 nonn,tabl %O A127572 1,2 %A A127572 _Gary W. Adamson_, Jan 19 2007 %E A127572 Edited by _Franklin T. Adams-Watters_, Aug 24 2011