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 A120897 #3 Mar 30 2012 18:36:58 %S A120897 1,3,10,33,106,336,1056,3296,10234,31648,97551,299888,919865,2816291, %T A120897 8608712,26278538,80120533,244022331,742525242,2257527861,6858558246, %U A120897 20822959508,63181453350,191601205342,580749971840,1759465640586 %N A120897 Row sums of triangle A120894 (cascadence of 1+x+x^2). %Y A120897 Cf. A120894, A120895, A120896. %K A120897 nonn %O A120897 0,2 %A A120897 _Paul D. Hanna_, Jul 14 2006