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A366612
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Number of divisors of 5^n-1.
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10
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3, 8, 6, 20, 12, 48, 6, 48, 24, 64, 6, 240, 6, 64, 96, 224, 12, 512, 24, 640, 48, 128, 12, 1152, 192, 64, 384, 320, 24, 6144, 12, 1024, 48, 128, 384, 10240, 24, 512, 48, 6144, 12, 18432, 12, 1280, 3072, 128, 6, 10752, 12, 4096, 192, 960, 24, 81920, 576, 1536
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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a(3)=6 because 5^3-1 has divisors {1, 2, 4, 31, 62, 124}.
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MAPLE
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a:=n->numtheory[tau](5^n-1):
seq(a(n), n=1..100);
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MATHEMATICA
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DivisorSigma[0, 5^Range[100]-1]
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PROG
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(PARI) a(n) = numdiv(5^n-1);
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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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