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 A137640 #3 Mar 30 2012 17:25:27 %S A137640 1,3,4,8,9,17,19,32,40,57,71,106,129,176 %N A137640 Row sums of triangle A137639. %F A137640 A026794 * A000005. (A026794 as an infinite lower triangular matrix and d(n) as a vector). %e A137640 a(4) = 8 = sum of row 4 terms of triangle A137639: (7 + 2 + 0 + 1). %e A137640 a(4) = 8 = (3, 1, 0, 1) dot (1, 2, 2, 3) = (3 + 2 + 0 + 3); where (3, 1, 0, 1) = row 4 of triangle A026794, the partition triangle and (1, 2, 2, 3) = the first 4 terms of A000005, d(n). %Y A137640 Cf. A000005, A026794, A137639. %K A137640 nonn %O A137640 1,2 %A A137640 _Gary W. Adamson_, Jan 31 2008