A328855 Number of factorizations of n into numbers with an odd number of distinct prime factors.

1, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 2, 1, 1, 1, 5, 1, 2, 1, 2, 1, 1, 1, 3, 2, 1, 3, 2, 1, 2, 1, 7, 1, 1, 1, 4, 1, 1, 1, 3, 1, 2, 1, 2, 2, 1, 1, 5, 2, 2, 1, 2, 1, 3, 1, 3, 1, 1, 1, 4, 1, 1, 2, 11, 1, 2, 1, 2, 1, 2, 1, 6, 1, 1, 2, 2, 1, 2, 1, 5, 5, 1, 1, 4, 1, 1, 1, 3, 1, 4

Offset

1,4

Links

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

Formula

Dirichlet g.f.: Product_{k>=1} 1 / (1 - A030230(k)^(-s)).

Example

a(8) = 3 because 8 = 2 * 4 = 2 * 2 * 2.

Crossrefs

Cf. A001055, A030230, A050330, A328856.

Sequence in context: A322453 A327012 A351219 * A327658 A319786 A321271

Adjacent sequences: A328852 A328853 A328854 * A328856 A328857 A328858

Keyword

nonn

Author

Ilya Gutkovskiy, Oct 28 2019

Status

approved