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A366652
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Number of divisors of 8^n-1.
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10
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2, 6, 4, 24, 8, 32, 12, 96, 8, 96, 16, 512, 16, 144, 64, 768, 32, 160, 16, 4608, 96, 384, 16, 8192, 128, 192, 64, 9216, 64, 4096, 8, 6144, 256, 1536, 1536, 10240, 64, 384, 512, 73728, 32, 6144, 32, 24576, 1024, 384, 64, 262144, 64, 12288, 256, 147456, 256
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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 8^5-1 has divisors {1, 7, 31, 151, 217, 1057, 4681, 32767}.
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MAPLE
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a:=n->numtheory[tau](8^n-1):
seq(a(n), n=1..100);
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MATHEMATICA
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DivisorSigma[0, 8^Range[100]-1]
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PROG
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(PARI) a(n) = numdiv(8^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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