A342395 a(n) = Sum_{k=1..n} k^(n/gcd(k,n)).

1, 3, 12, 90, 1305, 15713, 376768, 6163324, 176787369, 3769360335, 142364319636, 3152514811878, 154718778284161, 4340009168261557, 210971169749009040, 7281661102087491416, 435659030617933827153, 14181101408651996188995

Offset: 1

Author

Seiichi Manyama, Mar 10 2021

Keywords

• nonn
• easy

Crossrefs

Cf. A121706, A332620, A342389, A342396.

Programs

Mathematica

a[n_] := Sum[k^(n/GCD[k, n]), {k, 1, n}]; Array[a, 18] (* Amiram Eldar, Mar 10 2021 *)

PARI

a(n) = sum(k=1, n, k^(n/gcd(k, n)));

Formula

If p is prime, a(p) = A121706(p) + p.