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A247939
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Sum of divisors of 2^prime(n)+1.
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1
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6, 13, 48, 176, 2736, 10928, 174768, 699056, 11184816, 727960800, 2863311536, 183355069408, 2967356682528, 11728124029616, 188313058624992, 12121838249371488, 768906329487027264, 3074457345618258608, 196765296972010592800, 3148244377723715041632
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OFFSET
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1,1
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COMMENTS
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b-file computed with factorizations in Wagstaff link. a(166) corresponding to 2^983+1 is currently the first unknown term. - Jens Kruse Andersen, Sep 28 2014
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LINKS
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FORMULA
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MAPLE
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MATHEMATICA
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Table[DivisorSigma[1, 2^Prime[n] + 1], {n, 1, 20}]
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PROG
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(Magma) [SumOfDivisors(2^p+1): p in PrimesUpTo(100)];
(PARI) vector(50, n, sigma(2^prime(n)+1)) \\ Derek Orr, Sep 27 2014
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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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