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 A047149 #5 Mar 30 2012 18:56:53 %S A047149 1,3,13,68,395,2383,14628,91002,572629,3635105,23230955,149252778, %T A047149 963125552,6238012172,40529533578,264038158806,1724159758595, %U A047149 11281813669783,73955009216581,485575827838870,3192818972511443 %N A047149 T(2n,n), array T as in A047140. %K A047149 nonn %O A047149 0,2 %A A047149 _Clark Kimberling_. Definition revised Dec 08 2006