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 A028490 #1 Dec 11 1999 03:00:00 %S A028490 2,3,5,19,97,103,317,353,701,9739 %N A028490 Erroneous version of A004064. %K A028490 dead %O A028490 0,1