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 A283055 #16 Apr 27 2020 19:45:56 %S A283055 1,4,22,137,607,2816,13616 %N A283055 Erroneous version of A272435. %K A283055 dead %O A283055 1,2