A230238 Numbers n such that phi(sigma(n)) + sigma(phi(n)) is the mean value of phi(n) and sigma(n).

6, 37716, 58710, 120930, 1269432, 2663850, 3349170, 3995244, 4353426, 5468424, 7191072, 7437960, 7564128, 7613892, 8354610, 8810490, 10309410, 11917620, 13573500, 21970980, 23877450, 24712350, 38801790, 49394556, 56208264, 56809578, 57339150, 66379170, 77966616, 91549710, 93657564

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..111 (terms < 3*10^10)

Mathematica

Do[If[DivisorSigma[1, n]+EulerPhi[n]==2(EulerPhi[DivisorSigma[1, n]]+DivisorSigma[1, EulerPhi[n]]), Print[n]], {n, 100000000}]

Crossrefs

Cf. A000010, A000203, A062401, A062402, A230237.

Sequence in context: A182790 A306667 A172812 * A256511 A295788 A295789

Adjacent sequences: A230235 A230236 A230237 * A230239 A230240 A230241

Keyword

nonn

Author

Farideh Firoozbakht, Oct 16 2013

Status

approved