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A057938 Number of prime factors of 6^n + 1 (counted with multiplicity). 9
1, 1, 2, 1, 3, 3, 4, 2, 3, 3, 2, 2, 4, 3, 5, 3, 3, 6, 3, 3, 6, 4, 3, 4, 4, 4, 5, 5, 4, 9, 2, 3, 6, 3, 11, 5, 4, 3, 9, 5, 4, 7, 2, 3, 7, 5, 2, 7, 7, 6, 8, 4, 5, 10, 8, 6, 7, 3, 2, 6, 3, 2, 10, 3, 8, 11, 5, 5, 6, 7, 4, 5, 6, 5, 10, 5, 6, 11, 6, 6, 8, 4, 5, 8, 8, 5, 11, 4, 3, 16, 12, 4, 5, 5, 10, 4, 4, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Max Alekseyev, Table of n, a(n) for n = 1..418 (first 408 terms from Amiram Eldar)

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

FORMULA

a(n) = A057955(2n) - A057955(n). - T. D. Noe, Jun 19 2003

a(n) = A001222(A062394(n)). - Amiram Eldar, Feb 02 2020

MATHEMATICA

PrimeOmega[6^Range[100]+1] (* Harvey P. Dale, Mar 10 2013 *)

PROG

(MAGMA) f:=func<n|&+[p[2]: p in Factorization(n)]>; [f(6^n + 1):n in [1..100]]; // Marius A. Burtea, Feb 02 2020

CROSSREFS

bigomega(b^n+1): A057934 (b=10), A057935 (b=9), A057936 (b=8), A057937 (b=7), this sequence (b=6), A057939 (b=5), A057940 (b=4), A057941 (b=3), A054992 (b=2).

Cf. A001222, A057955, A062394, A274904.

Sequence in context: A308057 A097686 A082666 * A144623 A340284 A218975

Adjacent sequences:  A057935 A057936 A057937 * A057939 A057940 A057941

KEYWORD

nonn

AUTHOR

Patrick De Geest, Oct 15 2000

STATUS

approved

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Last modified May 18 23:31 EDT 2022. Contains 353826 sequences. (Running on oeis4.)