A371243 Number of factorizations of n into factors > 2.

1, 0, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 2, 2, 1, 1, 3, 2, 1, 3, 2, 1, 3, 1, 2, 2, 1, 2, 5, 1, 1, 2, 3, 1, 3, 1, 2, 4, 1, 1, 5, 2, 2, 2, 2, 1, 4, 2, 3, 2, 1, 1, 6, 1, 1, 4, 4, 2, 3, 1, 2, 2, 3, 1, 7, 1, 1, 4, 2, 2, 3, 1, 5, 5, 1, 1, 6, 2, 1, 2, 3, 1, 7, 2, 2, 2, 1, 2, 7, 1, 2, 4, 5, 1, 3, 1, 3, 5

Offset: 1

Author

Ilya Gutkovskiy, Mar 16 2024

Keywords

• nonn

Examples

			a(24) = 3: 24 = 3*8 = 4*6.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A001055, A008483, A078012, A371209, A371244, A371245.

Programs

PARI

A371243(n, m=n) = if(1==n, 1, my(s=0); fordiv(n, d, if((d>2)&&(d<=m), s += A371243(n/d, d))); (s)); \\ Antti Karttunen, Nov 28 2024

Formula

Dirichlet g.f.: Product_{k>=3} 1 / (1 - k^(-s)).

Extensions

More terms from Antti Karttunen, Nov 28 2024