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A177892
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The number of distinct prime factors in Lucas-Lehmer number A003010(n).
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1
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OFFSET
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0,2
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COMMENTS
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a(9)>3 and a(10)>2: results from www.factordb.com. - R. J. Mathar, Dec 15 2010
a(11)=4, factorization added to www.factordb.com. - Sean A. Irvine, Mar 25 2011
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LINKS
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Table of n, a(n) for n=0..8.
Dario Alejandro Alpern, Factorization using the Elliptic Curve Method (along with sigma_0, sigma_1 and phi functions)
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FORMULA
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a(n) = A001221(A003010(n)).
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MATHEMATICA
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Table[PrimeNu[Ceiling[(2 + Sqrt[3])^(2^n)]], {n, 0, 5}] (* G. C. Greubel, May 16 2017 *)
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PROG
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(PARI) a=4; until(a=a^2-2, print1(omega(a)", ")) \\ M. F. Hasler, Dec 14 2010
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CROSSREFS
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Cf. A000040, A003010, A177876.
Sequence in context: A056160 A106245 A129568 * A236433 A117122 A122828
Adjacent sequences: A177889 A177890 A177891 * A177893 A177894 A177895
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KEYWORD
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nonn,hard,more
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AUTHOR
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G. L. Honaker, Jr., Dec 14 2010
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STATUS
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approved
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