A076333 - OEIS

A076333

Squarefree kernels of nonsquarefree numbers.

2, 2, 3, 6, 2, 6, 10, 6, 5, 3, 14, 2, 6, 10, 22, 15, 6, 7, 10, 26, 6, 14, 30, 21, 2, 34, 6, 15, 38, 10, 3, 42, 22, 30, 46, 6, 14, 33, 10, 26, 6, 14, 58, 39, 30, 11, 62, 5, 42, 2, 66, 15, 34, 70, 6, 21, 74, 30, 38, 51, 78, 10, 6, 82, 42, 13, 57, 86, 35, 22, 30, 46, 94, 21, 6, 14, 66

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OFFSET

1,1

LINKS

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

FORMULA

a(n) = A007947(A013929(n)).

Sum_{k=1..n} a(k) ~ c * n^2 / 2, where c = (A065463 - 6/Pi^2)/(1 - 6/Pi^2)^2 = 0.627858264532... . - Amiram Eldar, Dec 09 2023

MATHEMATICA

f[n_] := If[(r = Times @@ FactorInteger[n][[;; , 1]]) < n, r , 0]; Select[f /@ Range[200], # > 0 &] (* Amiram Eldar, Sep 07 2020 *)

CROSSREFS

Cf. A007947, A013929.