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Numbers n such that n | sigma(n) - d(n) + phi(n).
1

%I #11 Apr 26 2017 11:06:23

%S 1,2,27,65120,3332064,21940224,351952896,123346213728

%N Numbers n such that n | sigma(n) - d(n) + phi(n).

%p with(numtheory): A056013:=n->`if`(sigma(n)-tau(n)+phi(n) mod n = 0, n, NULL): seq(A056013(n), n=1..10^5); # _Wesley Ivan Hurt_, Apr 26 2017

%t Do[If[Mod[DivisorSigma[1, n]-DivisorSigma[0, n]+EulerPhi[n], n]==0, Print[n]], {n, 1, 10^7}]

%Y Cf. A000005, A000010, A000203.

%K nonn

%O 1,2

%A _Robert G. Wilson v_, Jul 24 2000

%E a(6)-a(8) from _Donovan Johnson_, Nov 12 2012