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A177876 The number of distinct prime factors in Lucas-Lehmer numbers A003010(k-2) divisible by 2^k-1. 1
2, 3, 3, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(5) of this sequence will require the factorization of A003010(15), an 18742-digit integer divisible by 2^17-1.

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

a(1)=2 because A003010(1)=14, contains exactly 2 distinct prime factors;

a(2)=3 because A003010(3)=37634, contains exactly 3 distinct prime factors;

a(3)=3 because A003010(5)=2005956546822746114, contains exactly 3 distinct prime factors;

a(4)=4 because A003010(11)=the associated 1172-digit Lucas-Lehmer number, contains exactly 4 distinct prime factors.

CROSSREFS

Cf. A000040, A000668, A003010, A177874, A177875, A177879, A177892

Sequence in context: A096393 A010120 A012887 * A079633 A285891 A060573

Adjacent sequences:  A177873 A177874 A177875 * A177877 A177878 A177879

KEYWORD

nonn,hard,bref,more

AUTHOR

G. L. Honaker, Jr., Dec 13 2010

STATUS

approved

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Last modified July 15 20:24 EDT 2019. Contains 325056 sequences. (Running on oeis4.)