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 A156878 #9 Nov 06 2022 07:48:13
%S A156878 0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,2,2,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,
%T A156878 4,4,5,5,5,5,5,5,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,7,7,7,7,7,7,8,8,
%U A156878 8,8,9,9,10,10,10,10,10,10,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11
%N A156878 Number of primes <= n that are neither safe primes and nor Sophie Germain primes.
%H A156878 Reinhard Zumkeller, <a href="/A156878/b156878.txt">Table of n, a(n) for n = 1..10000</a>
%F A156878 a(n) = A000720(n) - A156876(n).
%e A156878 a(120) = #{13,17,19,31,37,43,61,67,71,73,79,97,10,103,109} = 15.
%Y A156878 Cf. A059500, A005384, A005385.
%Y A156878 Cf. A000720, A156876.
%K A156878 nonn
%O A156878 1,17
%A A156878 _Reinhard Zumkeller_, Feb 18 2009