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 A108409 #2 Mar 30 2012 18:41:21 %S A108409 5,7,11,13,19,20,21,26,37,48,50,51,61,65,68,75,76,80,81,93,98,101,110, %T A108409 113,114,121,127,128,129,135,143,146,147,149,151,163,167,171,175,179, %U A108409 184,185,188,194,201,205,208,209,218,219,220,221,251,254,257,263,264 %N A108409 Complement of A108408. Missing values in A108407. %K A108409 nonn %O A108409 1,1 %A A108409 _Ralf Stephan_, Jun 03 2005