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 A307289 #9 Apr 09 2019 03:20:18 %S A307289 2,17,230,4895 %N A307289 Erroneous version of A006227. %H A307289 Schwarzenberger, R. L. E. "<a href="https://doi.org/10.1112/blms/16.3.209">Colour symmetry</a>." Bulletin of the London Mathematical Society 16.3 (1984): 216-229. %K A307289 dead %O A307289 1,1