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A345450
Sum of the semiprime divisors of n whose square does not divide n.
0
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, 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, 8, 4, 12, 0, 8, 0, 4, 8, 8, 4, 12, 0, 4, 0, 4, 0, 16, 4, 4, 4, 8, 0, 16
OFFSET
1,4
COMMENTS
a(p) = 0 for p prime.
FORMULA
a(n) = Sum_{d|n, d^2 does not divide n} d * [Omega(d) = 2], where [ ] is the Iverson bracket.
CROSSREFS
Cf. A001358.
Sequence in context: A035638 A347156 A292142 * A098002 A241658 A256719
KEYWORD
nonn
AUTHOR
Wesley Ivan Hurt, Jun 19 2021
STATUS
approved