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 A129020 #3 Mar 30 2012 16:50:41 %S A129020 0,2,7,24,77,222,591 %N A129020 A129019(n)-A129018(n). %D A129020 J. R. Dias, The Periodic Table Set as a Unifying Concept in Going from Benzenoid Hydrocarbons to Fullerene Carbons, in "The Periodic Table: Into the 21st Century", Edited by D. H. Rouvray and R. B. King, Research Studies Press Ltd, Baldock, Hertfordshire, England, 2004, 371-396. %Y A129020 Cf. A129012-A129021. %K A129020 nonn %O A129020 0,2 %A A129020 _N. J. A. Sloane_, based on email from Jerry R. Dias (DiasJ(AT)umkc.edu), May 08 2007