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Search: id:A059886
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| A059886 |
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a(n)=|{m : multiplicative order of 4 mod m=n}|. |
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+0
4
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| 2, 2, 4, 4, 6, 16, 6, 8, 26, 38, 14, 68, 6, 54, 84, 16, 6, 462, 6, 140, 132, 110, 14, 664, 120, 118, 128, 188, 62, 4456, 6, 96, 364, 118, 498, 7608, 30, 118, 180, 568, 30, 9000, 30, 892, 3974, 494, 62, 5360, 24, 8024
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OFFSET
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1,1
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COMMENT
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The multiplicative order of a mod m, GCD(a,m)=1, is the smallest natural number d for which a^d = 1 (mod m). a(n)=number of orders of degree-n monic irreducible polynomials over GF(4).
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FORMULA
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a(n)=Sum_{ d divides n } mu(n/d)*tau(4^d-1), (mu(n) = Moebius function A008683, tau(n) = number of divisors of n A000005).
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EXAMPLE
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a(1)=|{1,3}|=2, a(2)=|{5,15}|=2, a(3)=|{7,9,21,63}|=4, a(4)=|{17,51,85,255}|=4,...
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CROSSREFS
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Cf. A000005, A008683, A027377, A053447, A058948, A059499, A059885, A059887-A059892.
Sequence in context: A066813 A033732 A033752 this_sequence A085893 A060028 A099770
Adjacent sequences: A059883 A059884 A059885 this_sequence A059887 A059888 A059889
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)Eunet.yu), Feb 06 2001
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