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A366633
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Number of divisors of 7^n-1.
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11
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4, 10, 12, 36, 8, 60, 16, 84, 64, 80, 16, 864, 8, 160, 96, 384, 16, 640, 16, 1536, 96, 160, 32, 16128, 32, 80, 1280, 1152, 32, 3840, 32, 1728, 384, 80, 128, 18432, 32, 160, 192, 14336, 32, 7680, 16, 4608, 2048, 160, 16, 147456, 256, 640, 768, 1152, 32, 25600
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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(5)=8 because 7^5-1 has divisors {1, 2, 3, 6, 2801, 5602, 8403, 168061}.
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MAPLE
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a:=n->numtheory[tau](7^n-1):
seq(a(n), n=1..100);
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MATHEMATICA
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DivisorSigma[0, 7^Range[100]-1]
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PROG
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(PARI) a(n) = numdiv(7^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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