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 A217691 #30 Nov 02 2013 19:30:05 %S A217691 2,3,19,23,31,43,59,61,73,83,103,107,109,113,151,163,179,181,197,199, %T A217691 233,241,269,271,277,281,283,313,317,349,353,379,383,409,421,433,443, %U A217691 449,461,463,503,509,523,571,577,593,599,601,617,619,643,647,659,661,677 %N A217691 Primes in A217689. %C A217691 Apart from the initial 2, the odd terms of A217689. - _M. F. Hasler_, Oct 19 2012 %F A217691 If A(n) is the number of terms not exceeding n, then heuristically A(n) is equivalent to log(2)*pi(n), as n tends to infinity. Practically, an approximation of A(n)is given by the expression n*log(2)/log(n*log(n)). %Y A217691 Cf. A217689. %K A217691 nonn %O A217691 1,1 %A A217691 _Vladimir Shevelev_, Oct 11 2012