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 A120902 #3 Mar 30 2012 18:36:58 %S A120902 1,5,23,103,450,1932,8196,34468,143997,598463,2476936,10216818, %T A120902 42023225,172436363,706132290,2886574198,11781962631,48025519977, %U A120902 195530083266,795241236228,3231290822280,13118557603984,53218706064038 %N A120902 Row sums of triangle A120898 (cascadence of 1+2x+x^2). %Y A120902 Cf. A120898, A120899, A120900, A120901. %K A120902 nonn %O A120902 0,2 %A A120902 _Paul D. Hanna_, Jul 14 2006