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 A047006 #4 Mar 30 2012 18:56:51 %S A047006 1,2,5,16,53,186,665,2430,8981,33556,126300,478468,1821677,6965726, %T A047006 26730639,102895388,397130997,1536321264,5955477230,23128018490, %U A047006 89962619148,350442078972,1366907765382,5337995113404,20868301796085 %N A047006 T(n,n+1), array T given by A047000. %K A047006 nonn %O A047006 0,2 %A A047006 _Clark Kimberling_