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 A091621 #3 Mar 30 2012 17:37:13 %S A091621 1,3,7,18,43,102,241,563,1293,2960,6722,15140,33919,75576,167490, %T A091621 369556,811953,1776993,3875220,8423004,18251468,39435686,84980633, %U A091621 182669118,391736024,838237802,1789955529,3814790598,8115210879 %N A091621 Row sums of triangle A091615. %K A091621 nonn %O A091621 1,2 %A A091621 _Christian G. Bower_, Jan 23 2004