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Search: id:A059887
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| A059887 |
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a(n)=|{m : multiplicative order of 5 mod m=n}|. |
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+0
2
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| 3, 5, 3, 12, 9, 37, 3, 28, 18, 47, 3, 180, 3, 53, 81, 176, 9, 446, 21, 564, 39, 117, 9, 884, 180, 53, 360, 244, 21, 5959, 9, 800, 39, 111, 369, 9536, 21, 483, 39, 5476, 9, 18289, 9, 1140, 2958, 111, 3, 9424, 6, 3852
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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(5).
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FORMULA
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a(n)=Sum_{d|n} mu(n/d)*tau(5^d-1), (mu(n) = Moebius function A008683, tau(n) = number of divisors of n A000005).
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CROSSREFS
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Cf. A000005, A008683, A001692, A053447, A058945, A059499, A059885, A059886, A059888-A059892.
Adjacent sequences: A059884 A059885 A059886 this_sequence A059888 A059889 A059890
Sequence in context: A089730 A105445 A049072 this_sequence A023585 A089948 A023583
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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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