A350996 - OEIS

A350996

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

1, 5, 14, 22, 47, 83, 132, 148, 175, 275, 396, 468, 637, 833, 1058, 1090, 1379, 1487, 1848, 2048, 2489, 2973, 3502, 3646, 3771, 4447, 4528, 4920, 5761, 6661, 7622, 7686, 8775, 9931, 11156, 11372, 12741, 14185, 15706, 16106, 17787, 19551, 21400, 22368, 23043, 25159

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OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

Wikipedia, Radical of an integer.

FORMULA

a(n) = Sum_{k=1..n} A064549(k).

a(n) ~ c * n^3 / 3, where c = A065463. - Amiram Eldar, Dec 09 2023

EXAMPLE

a(4) = 22; a(4) = Sum_{k=1..4} k * rad(k) = 1*rad(1) + 2*rad(2) + 3*rad(3) + 4*rad(4) = 1*1 + 2*2 + 3*3 + 4*2 = 22.

MATHEMATICA