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 A291967 #4 Sep 07 2017 12:14:20 %S A291967 1,1,3,21,651,657653,210065930571 %N A291967 Erroneous version of A001699. %H A291967 Mayfawny Bergmann, <a href="http://scholar.rose-hulman.edu/rhumj/vol15/iss2/1/"> Efficiency of Lossless Compression of a Binary Tree via its Minimal Directed Acyclic Graph Representation</a>. Rose-Hulman Undergraduate Mathematics Journal: Vol. 15 : Iss. 2, Article 1. (2014). %K A291967 dead %O A291967 0,3