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 A089375 #4 Jan 09 2009 03:00:00 %S A089375 31,421,71,131,191,2551,311,391331,431,48241612864321,911371,971,1031 %N A089375 Duplicate of A069582. %K A089375 dead %O A089375 1,1