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 A054538 #3 Mar 30 2012 16:48:46 %S A054538 1,1,2,2,4,5,10,15,28,47,90,158,298,548,1034,1928,3658,6899,13136, %T A054538 24970,47710,91181,174858,335546,645436,1242767,2397044,4628198, %U A054538 8948416,17318417,33555466,65075294,126324496,245426708 %N A054538 A000013 / 2. %K A054538 nonn %O A054538 1,3 %A A054538 _N. J. A. Sloane_, Apr 10 2000