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 A168485 #5 Mar 30 2012 18:52:04 %S A168485 0,1,1,3,4,5,3,7,2,9,5,11,6,13,7,15,4,17,9,19,80,21,11,23,6,25,13,27, %T A168485 14,29,15,31,8,33,17,35,36,37,19,39,10,41,21,43,22,45,23,47,12,49,25, %U A168485 51,104,53,27,55,14,57,29,59 %N A168485 A165342(3n)/3. %F A168485 a(n) = A166720(n)/3. %F A168485 a(2n+1) = 2n+1. %K A168485 nonn %O A168485 0,4 %A A168485 _Paul Curtz_, Nov 27 2009