A318674 Sum of squarefree divisors of n that have an even number of prime factors.

1, 1, 1, 1, 1, 7, 1, 1, 1, 11, 1, 7, 1, 15, 16, 1, 1, 7, 1, 11, 22, 23, 1, 7, 1, 27, 1, 15, 1, 32, 1, 1, 34, 35, 36, 7, 1, 39, 40, 11, 1, 42, 1, 23, 16, 47, 1, 7, 1, 11, 52, 27, 1, 7, 56, 15, 58, 59, 1, 32, 1, 63, 22, 1, 66, 62, 1, 35, 70, 60, 1, 7, 1, 75, 16, 39, 78, 72, 1, 11, 1, 83, 1, 42, 86, 87, 88, 23, 1, 32, 92, 47

Offset

1,6

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Formula

a(n) = Sum_{d|n} [A008683(d) > 0]*d.

a(n) = A048250(n) - A318675(n).

For all n >= 1, a(n) <= A318676(n).

Prog

(PARI) A318674(n) = sumdiv(n, d, (1==moebius(d))*d);

Crossrefs

Cf. A048250, A166142, A284118, A291784, A318675, A318676.

Sequence in context: A367483 A348281 A317940 * A284118 A165725 A214685

Adjacent sequences: A318671 A318672 A318673 * A318675 A318676 A318677

Keyword

nonn

Author

_Antti Karttunen_, Sep 04 2018

Status

approved