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 A175968 #2 Mar 30 2012 19:00:24 %S A175968 3,4,5,7,8,9,10,11,13,14,15,16,17,18,19,21,22,23,24,25,26,27,28,30,31, %T A175968 32,33,34,35,36,37,38,40,41,42,43,44,45,46,47,48,49,50,52,53,54,55,56, %U A175968 57,58,59,60,61,62,63,64,66,67,68,69,70,71,72,73,74,75,76,77,78,79 %N A175968 Complement of A175967(n), where A175967(n) = the lexicographically earliest sequence with first differences as increasing sequence of nonprimes A018252(n). %Y A175968 Cf. A175965, A175966, A175967, A014284, A175969, A051349, A175970. %K A175968 nonn %O A175968 1,1 %A A175968 _Jaroslav Krizek_, Oct 31 2010