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 A017149 #7 May 11 2007 03:00:00 %S A017149 7,15,23,31,39,47,55,63,71,79,87,95,103,111,119,127,135,143,151,159 %N A017149 Duplicate of A004771. %K A017149 dead %O A017149 0,1