A341036 a(n) = Sum_{k=1..n} gcd(k,n)^(k-2).

1, 2, 5, 19, 129, 1306, 16813, 262181, 4783059, 100000214, 2357947701, 61917372083, 1792160394049, 56693912393474, 1946195068811453, 72057594039243049, 2862423051509815809, 121439531096661117354, 5480386857784802185957

Offset: 1

Author

Seiichi Manyama, Mar 13 2021

Keywords

• nonn

Crossrefs

Cf. A000010, A018804, A342370, A342432, A342449.

Programs

Mathematica

a[n_] := Sum[GCD[k, n]^(k - 2), {k, 1, n}]; Array[a, 20] (* Amiram Eldar, Mar 13 2021 *)

PARI

a(n) = sum(k=1, n, gcd(k, n)^(k-2));