A285799 Number of partitions of n into parts with an odd number of distinct prime divisors.

1, 0, 1, 1, 2, 2, 3, 4, 6, 7, 9, 12, 15, 19, 23, 29, 37, 44, 54, 66, 80, 96, 115, 138, 165, 196, 231, 275, 322, 380, 444, 520, 608, 706, 821, 952, 1102, 1272, 1467, 1688, 1941, 2226, 2549, 2917, 3329, 3798, 4324, 4918, 5587, 6337, 7180, 8125, 9184, 10369, 11695, 13174, 14828, 16671, 18723, 21011, 23551

Offset: 0

Author

Ilya Gutkovskiy, Apr 26 2017

Keywords

• nonn

Examples

			a(7) = 4 because we have [7], [5, 2], [4, 3] and [3, 2, 2].
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000
• Index entries for related partition-counting sequences

Crossrefs

Cf. A001156 (number of partitions into parts with an odd number of divisors), A030230, A285798.

Programs

Mathematica

nmax = 60; CoefficientList[Series[Product[1/(1 - Boole[OddQ[PrimeNu[k]]] x^k), {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} 1/(1 - x^A030230(k)).