A347416 a(n) = Sum_{k=1..n} floor((n/k)^n).

1, 5, 31, 276, 3238, 47463, 830415, 16845619, 388198577, 10009945747, 285452668383, 8918294580680, 302912273410475, 11112687415252836, 437907284782655738, 18447025981637731050, 827246579683710818081, 39346558272075085340201, 1978423430905859200399397

Offset: 1

Author

Seiichi Manyama, Aug 31 2021

Keywords

• nonn

Examples

			a(3) = [(3/1)^3] + [(3/2)^3] + [(3/3)^3] = 27 + 3 + 1 = 31.
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..386

Crossrefs

Cf. A006218, A153818, A332469, A344675, A347415.

Programs

Mathematica

a[n_] := Sum[Floor[(n/k)^n], {k, 1, n}]; Array[a, 20] (* Amiram Eldar, Aug 31 2021 *)

PARI

a(n) = sum(k=1, n, n^n\k^n);

Formula

a(n) ~ n^n. - Vaclav Kotesovec, Sep 14 2021