A362628 a(n) = Sum_{d|n, phi(d)|n} d.

1, 3, 1, 7, 1, 12, 1, 15, 1, 3, 1, 28, 1, 3, 1, 31, 1, 39, 1, 22, 1, 3, 1, 60, 1, 3, 1, 7, 1, 12, 1, 63, 1, 3, 1, 91, 1, 3, 1, 50, 1, 33, 1, 7, 1, 3, 1, 124, 1, 3, 1, 7, 1, 120, 1, 15, 1, 3, 1, 43, 1, 3, 1, 127, 1, 12, 1, 7, 1, 3, 1, 195, 1, 3, 1, 7, 1, 12, 1, 106, 1, 3, 1, 140

Offset: 1

Author

Wesley Ivan Hurt, Apr 28 2023

Keywords

• nonn
• easy

Crossrefs

Cf. A000010 (phi), A069932, A362470.

Programs

Mathematica

a[n_] := DivisorSum[n, # &, Divisible[n, EulerPhi[#]] &]; Array[a, 100]

PARI

a(n) = sumdiv(n, d, if (!(n % eulerphi(d)), d)); \\ Michel Marcus, Apr 28 2023