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 A085122 #15 Jan 22 2020 20:09:23
%S A085122 0,-1,0,0,0,0,0,1,1,1,0,2,0,1,1,2,0,2,0,2,2,2,0,2,2,2,3,3,0,2,0,3,2,2,
%T A085122 3,3,0,3,4,3,0,4,0,3,4,3,0,4,3,5,3,5,0,3,3,3,3,3,0,3,0,4,3,4,3,4,0,5,
%U A085122 5,5,0,4,0,2,5,4,4,4,0,5,5,5,0,7,4,5,4,5,0,4,3,5,5,5,5,4,0,5,5,5,0,6,0,6,6,7,0,5,0,5,6,8,0,5,5,6,7,5,5,5,6,5,6,7,5,5,0,7
%N A085122 a(n) = PrimePi(sigma(n)-phi(n)) - (PrimePi(sigma(n)) - PrimePi(phi(n))), where PrimePi = A000720, sigma = A000203 and phi = A000010.
%C A085122 Scatterplot of this sequence shows interesting strata. - _Antti Karttunen_, Jan 22 2020
%H A085122 Antti Karttunen, <a href="/A085122/b085122.txt">Table of n, a(n) for n = 1..65537</a>
%F A085122 a(n) = A000720(A051612(n)) - (A070803(n) - A070804(n)) = A000720(A051612(n)) - A085343(n). - _Antti Karttunen_, Jan 22 2020
%t A085122 t=Table[PrimePi[DivisorSigma[1, w]-EulerPhi[w]]- (PrimePi[DivisorSigma[1, w]]-PrimePi[EulerPhi[w]]), {w, 1, 10000}]
%o A085122 (PARI) A085122(n) = (primepi(sigma(n)-eulerphi(n)) - (primepi(sigma(n))-primepi(eulerphi(n)))); \\ _Antti Karttunen_, Jan 22 2020
%Y A085122 Cf. A000010, A000203, A000720, A051612, A070803, A070804, A085343.
%K A085122 sign,look
%O A085122 1,12
%A A085122 _Labos Elemer_, Jul 11 2003
%E A085122 Name edited by _Antti Karttunen_, Jan 22 2020