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 A092585 #21 Jun 20 2025 10:45:21
%S A092585 2,4,16,64,151,449,3403,4096,4267,9307,35905,65536,247285,262144,
%T A092585 17625601,33126625,399288961,649232833,947278081,1073741824,
%U A092585 2102485441,4555788385,5203567081,6103058177,7115716609
%N A092585 Numbers k such that sigma(phi(k))-phi(sigma(k)) is nonzero and is divisible by (k-1), that is A065395(k)/(k-1) = (phi(sigma(k))-sigma(phi(k)))/(k-1) is a nonzero integer.
%e A092585 (sigma(phi(x))-phi(sigma(x)))/(x-1) is -1 if x=2,4,16,64,4096,65536,262144 and is 2 if x=151,449,3403, etc.
%t A092585 f[ x_] := EulerPhi[ DivisorSigma[1, x]] - DivisorSigma[1, EulerPhi[x]]; t = {}; Do[ s = f[n]; If[ s != 0 && Mod[ s, n - 1] == 0, Print[n]; AppendTo[t, n]], {n, 2*10^8}]; t
%Y A092585 Cf. A033632, A092584-A092588, A065395.
%K A092585 nonn,more
%O A092585 1,1
%A A092585 _Labos Elemer_, Mar 01 2004
%E A092585 More terms from _Robert G. Wilson v_, Mar 03 2004
%E A092585 a(17)-a(25) from _Donovan Johnson_, Mar 04 2013