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 A026331 #4 Mar 30 2012 18:56:06 %S A026331 1,6,30,161,882,4916,27729,157830,904706,5215310,30203901,175598997, %T A026331 1024234850,5990912280,35126915550,206399581434,1215040298106, %U A026331 7164651246340,42310256416456,250194442456101,1481274328929984,8779528511274564 %N A026331 a(n) = T(2n-1,n), where T is the array in A026323. %K A026331 nonn %O A026331 1,2 %A A026331 _Clark Kimberling_