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 A084986 #6 May 11 2007 03:00:00 %S A084986 11,19,41,61,89,101,109,149,181,191,199,401,409,419,449,461,491,499, %T A084986 601 %N A084986 Duplicate of A034844. %K A084986 dead %O A084986 1,1