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A007671 Numbers n such that 2^n + 2^(n + 1)/2 + 1 is prime.
(Formerly M2481)
6
1, 3, 5, 11, 19, 29, 157, 163, 283, 379, 997, 10141, 14699, 77291, 85237, 106693, 203789 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

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).

LINKS

Table of n, a(n) for n=1..17.

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

PROG

(PARI) is(n)=ispseudoprime(2^n+2^(n+1)/2+1) \\ Charles R Greathouse IV, Feb 17 2017

CROSSREFS

Cf. A057429.

Sequence in context: A048161 A284034 A051642 * A259589 A090471 A124098

Adjacent sequences:  A007668 A007669 A007670 * A007672 A007673 A007674

KEYWORD

hard,nonn

AUTHOR

N. J. A. Sloane, Robert G. Wilson v

EXTENSIONS

More terms from Robert G. Wilson v, Sep 07 2000

203789 found and proved prime by Mike Oakes, on Sep 28 2000.

STATUS

approved

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Last modified November 15 18:59 EST 2019. Contains 329149 sequences. (Running on oeis4.)