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 A129859 #4 Feb 18 2018 20:24:12 %S A129859 1,2,3,7,13,33,73,202,488,1441,3741,11496,31311,98607,278840,895137, %T A129859 2599071,8452620 %N A129859 Apparently an erroneous version of A007827. %D A129859 Joseph Felsenstein, Inferring Phylogenies. Sinauer Associates, Inc., 2004, p. 33. %K A129859 dead %O A129859 3,2