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 A168249 #4 Mar 30 2012 18:52:35 %S A168249 1,2,3,7,12,16,20,26,29,33,38,43,48,51,57,60,63,68,72,77,80,93,96,101, %T A168249 112,118,122,125,130,134,145,147,158,168,171,175,181,190,195,198,204, %U A168249 210,213,223,236,239,243,254,259,269,271,276,282,287,292,294,298,304 %N A168249 n-th single or isolated number minus n-th squarefree number. %F A168249 a(n)=A167706(n)-A005117(n). %K A168249 nonn %O A168249 1,2 %A A168249 _Juri-Stepan Gerasimov_, Nov 21 2009 %E A168249 All numbers beyond a(18) corrected by _R. J. Mathar_, Jun 04 2010