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 A168543 #4 Jul 12 2012 00:39:51 %S A168543 1,2,3,5,7,9,10,12,13,15,16,17,19,20,22,23,24,25,26,28,30,31,32,33,35, %T A168543 37,38,39,40,41,43,45,47,48,49,51,52,54,55,56,57,59,60,62,63,64,66,67, %U A168543 68,69,71,72,73,74,75,76,77,78,79,80,81,83,85,86,87,88,89,91,92,93,94 %N A168543 pi(n-th single or isolated number). %F A168543 a(n)=A000720(A167706(n)). %K A168543 nonn %O A168543 1,2 %A A168543 _Juri-Stepan Gerasimov_, Nov 29 2009 %E A168543 Corrected (25 inserted) by _R. J. Mathar_, Nov 30 2009