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A125707
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Numbers n such that A024528(n) is prime.
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1
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1, 2, 3, 4, 5, 7, 14, 15, 17, 23, 32, 36, 42, 309, 1384, 1588
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OFFSET
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1,2
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COMMENTS
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A024528(n) is the numerator of 1 + Sum[ 1/Prime[k], {k,1,n} ], or n-th elementary symmetric function of {1, prime(1), prime(2), ..., prime(n-1)}.
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LINKS
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Table of n, a(n) for n=1..16.
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MATHEMATICA
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f=1; Do[p=Prime[n]; f=f+1/p; g=Numerator[f]; If[PrimeQ[g], Print[{n, p, g}]], {n, 1, 50}]
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CROSSREFS
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Cf. A024528, A109628.
Sequence in context: A193769 A066661 A178767 * A039060 A092065 A044955
Adjacent sequences: A125704 A125705 A125706 * A125708 A125709 A125710
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KEYWORD
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hard,more,nonn
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AUTHOR
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Alexander Adamchuk, Feb 01 2007
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EXTENSIONS
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3 more terms from Ryan Propper (rpropper(AT)cs.stanford.edu), Feb 11 2008
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STATUS
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approved
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