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
Keywords
Examples
a(12) = 4 because Jacobsthal(12) = 1365 has prime factors {3, 5, 7, 13}.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..1122