A351047 a(n) = Sum_{k=1..n} n^rad(k).

1, 6, 39, 100, 3305, 54726, 958447, 2392776, 5375169, 10011102310, 311270518031, 804967791420, 304805198256481, 11910060539653290, 469042238075266815, 1229501390272865296, 830281003630789139585, 2193053904527215207698, 1983916064827419873906079

Offset: 1

Author

Wesley Ivan Hurt, Jan 30 2022

Keywords

• nonn

Examples

			a(4) = 100; a(4) = Sum_{k=1..4} 4^rad(k) = 4^rad(1) + 4^rad(2) + 4^rad(3) + 4^rad(4) = 4^1 + 4^2 + 4^3 + 4^2 = 100.
		

Links

• Wikipedia, Radical of an integer.

Crossrefs

Cf. A007947 (rad), A176031, A350996.

Programs

Mathematica

a[n_] := Sum[n^Times @@ FactorInteger[k][[;; , 1]], {k, 1, n}]; Array[a, 20] (* Amiram Eldar, Feb 01 2022 *)