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A057955 Number of prime factors of 6^n - 1 (counted with multiplicity). 2
1, 2, 2, 3, 3, 4, 2, 4, 4, 6, 3, 7, 3, 6, 6, 6, 5, 7, 3, 9, 4, 5, 5, 9, 6, 7, 6, 9, 2, 11, 3, 9, 6, 8, 7, 13, 6, 6, 6, 12, 3, 10, 5, 9, 11, 8, 4, 13, 5, 10, 9, 11, 4, 11, 7, 14, 7, 6, 4, 20, 4, 5, 10, 12, 9, 12, 3, 11, 8, 18, 2, 18, 5, 10, 12, 9, 6, 15, 4, 17, 8, 7, 8, 17, 10, 7, 7, 12, 4, 18, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..91.

S. S. Wagstaff, Jr., Main Tables from the Cunningham Project.

S. S. Wagstaff, Jr., The Cunningham Project

FORMULA

Mobius transform of A085031 - T. D. Noe, Jun 19 2003

MATHEMATICA

PrimeOmega[6^Range[100]-1] (* Harvey P. Dale, Dec 14 2015 *)

CROSSREFS

Cf. A057951-A057958, A046051.

Cf. A085031.

Sequence in context: A015135 A116619 A091220 * A305788 A116473 A006546

Adjacent sequences:  A057952 A057953 A057954 * A057956 A057957 A057958

KEYWORD

nonn

AUTHOR

Patrick De Geest, Nov 15 2000.

STATUS

approved

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Last modified November 16 23:51 EST 2018. Contains 317275 sequences. (Running on oeis4.)