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A056852
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a(n) = (p^p + 1)/(p + 1), where p = prime(n).
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3
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7, 521, 102943, 23775972551, 21633936185161, 45957792327018709121, 98920982783015679456199, 870019499993663001431459704607, 85589538438707037818727607157700537549449, 533411691585101123706582594658103586126397951, 277766709362573247738903423315679814371773581141321037961
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OFFSET
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2,1
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COMMENTS
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Are all terms pairwise coprime? If so, they induce a permutation of the natural numbers, as Fermat numbers do (see A343767).
Are all terms squarefree?
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LINKS
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FORMULA
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a(n) = Sum_{k=0..prime(n)-1} (-prime(n))^k.
a(n) = F(prime(n), 1)/F(prime(n), 0), where F(b, n) = b^b^n + 1 (i.e., F(b, n) is the n-th base-b Fermat number, see A129290). (End)
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MAPLE
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MATHEMATICA
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Table[ (Prime[ n ]^Prime[ n ] + 1)/(Prime[ n ] + 1), {n, 2, 11} ]
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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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