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A006599
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Numbers n such that 2^(2n+1) + 2^(n+1) + 1 is prime.
(Formerly M1358)
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1
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0, 1, 2, 5, 9, 14, 78, 81, 141, 189, 498, 5070, 7349
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OFFSET
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1,3
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COMMENTS
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Some of the larger entries may only correspond to probable primes.
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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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J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
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PROG
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(PARI) isok(n) = isprime(2^(2*n+1) + 2^(n+1) + 1); \\ Michel Marcus, Mar 28 2014
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CROSSREFS
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A108062 is essentially the same sequence.
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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