A122811 - OEIS

A122811

Number of prime factors (counted with multiplicity) of the smallest odd number with exactly n divisors.

0, 1, 2, 2, 4, 3, 6, 3, 4, 5, 10, 4, 12, 7, 6, 5, 16, 5, 18, 6, 8, 11, 22, 5, 8, 13, 6, 8, 28, 7, 30, 6, 12, 17, 10, 6, 36, 19, 14, 7, 40, 9, 42, 12, 8, 23, 46, 6, 12, 9, 18, 14, 52, 7, 14, 9, 20, 29, 58, 8, 60, 31, 10, 7, 16, 13, 66, 18, 24, 11, 70, 7, 72, 37, 10, 20, 16, 15, 78, 8, 8, 41

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OFFSET

1,3

COMMENTS

a(p) = p-1 for prime p.

This sequence first differs from A059975(n) at n=16, because 3^3.5.7 is less than 3.5.7.11. - Hugo van der Sanden, May 21 2010

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..2000 (calculated from the b-file at A038547)

FORMULA

a(n) = Omega(A038547(n)), where Omega(n) = A001222(n).

CROSSREFS

Cf. A001222, A038547, A122376, A059975.