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 A140584 #4 Mar 03 2013 14:31:27 %S A140584 1,3,5,6,9,10,13,12,15,18,21,20,25,26 %N A140584 Row sums of A140583. %e A140584 a(6) = 10 = sum of row 6 terms of triangle A140583: (1 + 4 + 2 + 1 + 1 + 1). %Y A140584 Cf. A140583. %K A140584 nonn,more %O A140584 1,2 %A A140584 _Gary W. Adamson_ and _Mats Granvik_, May 17 2008