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Sum of the semiprime divisors of n whose square does not divide n.
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%I #3 Jun 19 2021 14:08:04

%S 0,0,0,4,0,4,0,4,4,4,0,8,0,4,4,0,0,8,0,8,4,4,0,8,4,4,4,8,0,12,0,0,4,4,

%T 4,8,0,4,4,8,0,12,0,8,8,4,0,4,4,8,4,8,0,8,4,8,4,4,0,16,0,4,8,0,4,12,0,

%U 8,4,12,0,8,0,4,8,8,4,12,0,4,0,4,0,16,4,4,4,8,0,16

%N Sum of the semiprime divisors of n whose square does not divide n.

%C a(p) = 0 for p prime.

%F a(n) = Sum_{d|n, d^2 does not divide n} d * [Omega(d) = 2], where [ ] is the Iverson bracket.

%Y Cf. A001358.

%K nonn

%O 1,4

%A _Wesley Ivan Hurt_, Jun 19 2021