A369687 a(n) = Sum_{p|n, p prime} p^phi(n/p).

0, 2, 3, 2, 5, 7, 7, 4, 9, 21, 11, 13, 13, 71, 106, 16, 17, 73, 19, 41, 778, 1035, 23, 97, 625, 4109, 729, 113, 29, 362, 31, 256, 59170, 65553, 18026, 145, 37, 262163, 531610, 881, 41, 4874, 43, 1145, 22186, 4194327, 47, 6817, 117649, 1049201, 43047010, 4265, 53, 262873, 9780266, 6497

Offset

1,2

Links

Table of n, a(n) for n=1..56.

Mathematica

Table[DivisorSum[n, #^EulerPhi[n/#] &, PrimeQ[#] &], {n, 60}]

Prog

(Python)
from sympy import totient, primefactors
def A369687(n): return sum(p**totient(n//p) for p in primefactors(n)) # Chai Wah Wu, Jan 28 2024

Crossrefs

Cf. A000010 (phi), A347104.

Sequence in context: A058977 A337246 A347104 * A085818 A270709 A323382

Adjacent sequences: A369684 A369685 A369686 * A369688 A369689 A369690

Keyword

nonn,easy

Author

Wesley Ivan Hurt, Jan 28 2024

Status

approved