A328855 - OEIS

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A328855

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

1

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

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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