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 A068871 #3 May 11 2007 03:00:00 %S A068871 1,11,31,41,61,71,101,121,131,151,181,191,211,241,251,271,281,311,331 %N A068871 Duplicate of A004615. %K A068871 dead %O A068871 1,2