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A366769
Number of distinct prime divisors of A001045(n) (Jacobsthal numbers).
4
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
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
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 21 2023
STATUS
approved