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 A085341 #18 Jan 12 2025 17:36:35
%S A085341 0,1,0,2,0,2,0,2,2,3,0,4,0,3,3,5,0,5,0,5,3,3,0,8,2,4,3,7,0,10,0,7,4,5,
%T A085341 4,13,0,5,4,12,0,11,0,9,7,6,0,15,1,9,5,10,0,14,4,14,6,8,0,22,0,6,9,13,
%U A085341 5,16,0,11,5,15,0,24,0,9,9,13,3,18,0,20,8
%N A085341 Number of primes between sigma(n) and n inclusive.
%H A085341 Antti Karttunen, <a href="/A085341/b085341.txt">Table of n, a(n) for n = 1..65537</a>
%F A085341 a(n) = pi(sigma(n)) - pi(n) = A000720(A000203(n)) - A000720(n).
%e A085341 n = 12: sigma(n) = 28, pi(28) - pi(12) = 9 - 5 = 4.
%t A085341 Table[PrimePi[DivisorSigma[1,n]]-PrimePi[n],{n,90}] (* _Harvey P. Dale_, Aug 18 2015 *)
%o A085341 (PARI) a(n) = primepi(sigma(n)) - primepi(n); \\ _Michel Marcus_, Dec 15 2013
%Y A085341 Cf. A000720, A000203, A070803, A070804, A085342-A085347.
%K A085341 nonn
%O A085341 1,4
%A A085341 _Labos Elemer_, Jul 10 2003