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 A140704 #2 Mar 30 2012 17:25:28 %S A140704 1,4,1,4,1,1,10,4,1,1,4,1,1,1,1,16,7,4,1,1,1,4,1,1,1,1,1,1,20,10,4,4, %T A140704 1,1,1,1,10,4,4,1,1,1,1,1,1,16,7,4,4,4,1,1,1,1,1,4,1,1,1,1,1,1,1,1,1, %U A140704 1,40,22,13,7,4,4,1,1,1,1,1,1 %N A140704 A051731^3 * A000012. %C A140704 Row sums = A007430: (1, 5, 6, 16, 8, 30, 10,...). %C A140704 Left column = A007426: (1, 4, 4, 10, 4, 16, 4,...). %F A140704 A051731^3 * A000012 as infinite lower triangular matrices, where A051731 = the inverse Mobius transform and A000012 an infinite lower triangular matrix with all 1's. %e A140704 First few rows of the triangle are: %e A140704 1; %e A140704 4, 1; %e A140704 4, 1, 1; %e A140704 10, 4, 1, 1; %e A140704 4, 1, 1, 1, 1; %e A140704 16, 7, 4, 1, 1, 1; %e A140704 4, 1, 1, 1, 1, 1, 1; %e A140704 20, 10, 4, 4, 1, 1, 1, 1; %e A140704 10, 4, 4, 1, 1, 1, 1, 1, 1; %e A140704 ... %Y A140704 Cf. A051731, A007430, A007426. %K A140704 nonn,tabl %O A140704 1,2 %A A140704 _Gary W. Adamson_, May 24 2008