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A055386
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Smallest factor of (2n)^(2n) + 1.
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3
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5, 257, 13, 97, 101, 89, 29, 274177, 5, 148721, 5, 17, 53, 449, 17, 641, 13, 17, 5, 17, 5, 41, 29, 769, 41, 89, 13, 17, 5, 17, 5, 59649589127497217, 37, 41, 13, 97, 149, 17, 5, 15361, 5, 1753, 13, 17, 41, 449, 1129, 1153, 5, 17, 5, 1201, 17, 1777, 89, 4993, 41
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OFFSET
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1,1
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COMMENTS
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If we use the commonly accepted convention that 0^0 = 1, then a(0) = 2. - Chai Wah Wu, Jul 22 2019
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REFERENCES
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C. Stanley Ogilvy and John T. Anderson, Excursions in Number Theory. Dover. New York: 1988. Page 82.
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LINKS
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FORMULA
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EXAMPLE
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8^8 + 1 = 97 * 257 * 673, so a(4) = 97.
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MATHEMATICA
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Table[With[{k = 2 n}, FactorInteger[k^k + 1]][[1, 1]], {n, 1, 60, 1} (* Vincenzo Librandi, Jul 23 2013 *)
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PROG
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(PARI) a(n) = factor(n^n + 1)[1, 1] \\ Michel Marcus, Jul 23 2013
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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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