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 A131415 #2 Mar 30 2012 17:25:22 %S A131415 1,3,1,6,4,1,11,10,5,1,20,21,15,6,1,37,41,36,21,7,1,70,78,77,57,28,8, %T A131415 1,135,148,155,134,85,36,9,1,264,283,303,289,219,121,45,10,1,521,547, %U A131415 586,592,508,340,166,55,11,1 %N A131415 (A007318 * A000012) + (A000012 * A007318) - A007318. %C A131415 Left column = A006127: (1, 3, 6, 11, 20, 37,...). Row sums = A047859: (1, 4, 11, 27, 63,...). %F A131415 (A007318 * A000012) + (A000012 * A007318) - A007318 as infinite lower triangular matrices. %e A131415 First few rows of the triangle are: %e A131415 1; %e A131415 3, 1; %e A131415 6, 4, 1; %e A131415 11, 10, 5, 1; %e A131415 20, 21, 15, 6, 1; %e A131415 37, 41, 36, 21, 7, 1; %e A131415 ... %Y A131415 Cf. A007318, A000012, A006127, A047859. %K A131415 nonn,tabl %O A131415 0,2 %A A131415 _Gary W. Adamson_, Jul 08 2007