A345450 Sum of the semiprime divisors of n whose square does not divide n.

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.

Links

Table of n, a(n) for n=1..90.

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

Adjacent sequences: A345447 A345448 A345449 * A345451 A345452 A345453

Keyword

nonn

Author

Wesley Ivan Hurt, Jun 19 2021

Status

approved