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 A128259 #2 Mar 30 2012 17:25:19 %S A128259 1,2,1,1,2,1,2,1,3,1,1,0,0,4,1,2,3,1,0,5,1,1,0,0,0,0,6,1,2,1,3,1,0,0, %T A128259 7,1,1,2,1,0,0,0,0,8,1,2,1,0,4,1,0,0,0,9,1 %N A128259 Inverse Moebius transform of A128229. %C A128259 Row sums = sigma(n), A000203: (1, 3, 4, 7, 6, 12, 8,...) A128260 = A128229 * A051731 %F A128259 A051731 * A128229 %e A128259 First few rows of the triangle are: %e A128259 1; %e A128259 2, 1; %e A128259 1, 2, 1; %e A128259 2, 1, 3, 1; %e A128259 1, 0, 0, 4, 1; %e A128259 2, 3, 1, 0, 5, 1; %e A128259 ... %Y A128259 Cf. A128229, A051731, A000203, A128260. %K A128259 nonn,tabl %O A128259 1,2 %A A128259 _Gary W. Adamson_, Feb 21 2007