A366781 Number of prime divisors of A000073(n) (tribonacci numbers) (counted with multiplicity).

0, 0, 1, 2, 1, 1, 4, 3, 4, 1, 2, 6, 3, 3, 8, 5, 2, 3, 4, 4, 3, 6, 4, 3, 4, 4, 3, 8, 4, 5, 11, 6, 4, 4, 10, 5, 5, 5, 9, 4, 2, 4, 2, 6, 5, 4, 11, 11, 2, 6, 7, 9, 3, 5, 9, 6, 2, 3, 5, 8, 12, 5, 11, 12, 4, 2, 4, 6, 3, 3, 6, 6, 2, 10, 7, 8, 7, 5, 12, 7, 4, 2, 6, 4

Offset: 2

Author

Sean A. Irvine, Oct 22 2023

Keywords

• nonn

Examples

			a(8)=4 because the 8th tribonacci number 24 = 2^3*3 has 4 prime factors.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 2..365

Crossrefs

Cf. A000073, A001222, A022307, A366780, A366782.

Programs

Mathematica

PrimeOmega[LinearRecurrence[{1, 1, 1}, {1, 1, 2}, 84]] (* Amiram Eldar, Oct 23 2023 *)

Formula

a(n) = A001222(A000073(n)).