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 A087724 #7 May 15 2013 08:00:20
%S A087724 1,0,1,1,2,2,3,4,6,5,7,7,8,9,11,11,12,12,13,13,15,15,17,19,19,20,21,
%T A087724 20,21,23,24,26,26,28,29,29,30,31,32,33,33,34,35,35,35,37,40,41,41,42,
%U A087724 43,42,44,46,47,48,48,48,49,48,50,54,54,54,55,57,58,60,61,60,61,62,63,64
%N A087724 a(n) = -PrimePi(n) +floor( prime(n)/log(n))-2.
%F A087724 a(n) = A085581(n)-A000720(n) -2. - _R. J. Mathar_, May 15 2013
%p A087724 A087724 := proc(n)
%p A087724 floor( ithprime(n)/log(n))-numtheory[pi](n) -2 ;
%p A087724 end proc: # _R. J. Mathar_, May 15 2013
%t A087724 Digits=200 a[n_]=-PrimePi[n]+Floor[Prime[n]/Log[n]]-2 b=Table[a[n], {n, 2, Digits}]
%K A087724 nonn
%O A087724 2,5
%A A087724 _Roger L. Bagula_, Sep 29 2003