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A007671
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Numbers n such that 2^n + 2^(n + 1)/2 + 1 is prime.
(Formerly M2481)
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6
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1, 3, 5, 11, 19, 29, 157, 163, 283, 379, 997, 10141, 14699, 77291, 85237, 106693, 203789, 3704053
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OFFSET
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1,2
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REFERENCES
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J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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Table of n, a(n) for n=1..18.
J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
S. S. Wagstaff, Jr., The Cunningham Project
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PROG
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(PARI) is(n)=ispseudoprime(2^n+2^(n+1)/2+1) \\ Charles R Greathouse IV, Feb 17 2017
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CROSSREFS
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Cf. A057429.
Sequence in context: A048161 A284034 A051642 * A259589 A090471 A124098
Adjacent sequences: A007668 A007669 A007670 * A007672 A007673 A007674
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KEYWORD
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nonn,hard,more
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AUTHOR
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N. J. A. Sloane, Robert G. Wilson v
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EXTENSIONS
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More terms from Robert G. Wilson v, Sep 07 2000
203789 found and proved prime by Mike Oakes, on Sep 28 2000.
a(18) from Serge Batalov, Jun 16 2020
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STATUS
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approved
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