A366769 Number of distinct prime divisors of A001045(n) (Jacobsthal numbers).

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

Offset

1,6

Links

Amiram Eldar, Table of n, a(n) for n = 1..1122

Formula

a(n) = omega(Jacobsthal(n)) = A001221(A001045(n)).

Example

a(12) = 4 because Jacobsthal(12) = 1365 has prime factors {3, 5, 7, 13}.

Crossrefs

Cf. A001045, A001221, A022307, A086598, A364818, A366770.

Sequence in context: A303428 A223853 A023645 * A167865 A218654 A054571

Adjacent sequences: A366766 A366767 A366768 * A366770 A366771 A366772

Keyword

nonn

Author

Sean A. Irvine, Oct 21 2023

Status

approved