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 A004060 #4 Dec 11 1999 03:00:00 %S A004060 3,7,13,71,103,541,1019,1367,1627,4177,9011,9551 %N A004060 Erroneous version of A028491. %K A004060 dead %O A004060 1,1