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 A026649 #4 Mar 30 2012 18:56:09 %S A026649 1,3,8,36,114,558,1856,9384,31942,164322,566928,2948184,10262004, %T A026649 53761068,188306112,991821456,3490234182,18458523378,65190481904, %U A026649 345875613144,1225052975644,6516499594212,23134851823872,123325174525104 %N A026649 a(n) = T(2n,n), T given by A026648. %K A026649 nonn %O A026649 0,2 %A A026649 _Clark Kimberling_