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A059888
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a(n) = |{m : multiplicative order of 6 mod m=n}|.
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14
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2, 2, 2, 4, 4, 10, 2, 8, 12, 40, 6, 108, 6, 42, 40, 48, 30, 100, 6, 332, 10, 22, 30, 376, 26, 118, 48, 332, 2, 1436, 6, 448, 54, 222, 88, 7952, 62, 54, 54, 2680, 6, 698, 30, 476, 1476, 222, 14, 7632, 28, 438, 478, 1916, 14, 1872, 84, 11896, 118, 58, 14, 784452
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OFFSET
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1,1
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COMMENTS
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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).
Also, number of primitive factors of 6^n - 1. - Max Alekseyev, May 03 2022
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LINKS
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FORMULA
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a(n) = Sum_{ d divides n } mu(n/d)*tau(6^d-1), (mu(n) = Moebius function A008683, tau(n) = number of divisors of n A000005).
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MAPLE
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with(numtheory):
a:= n-> add(mobius(n/d)*tau(6^d-1), d=divisors(n)):
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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