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A006599 Numbers n such that 2^(2n+1) + 2^(n+1) + 1 is prime.
(Formerly M1358)
1
0, 1, 2, 5, 9, 14, 78, 81, 141, 189, 498, 5070, 7349 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Some of the larger entries may only correspond to probable primes.

Next term >= 10^4. - Jeppe Stig Nielsen, Mar 28 2014

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..13.

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) isok(n) = isprime(2^(2*n+1) + 2^(n+1) + 1); \\ Michel Marcus, Mar 28 2014

CROSSREFS

A108062 is essentially the same sequence.

Sequence in context: A068501 A048071 A051892 * A013933 A101201 A184535

Adjacent sequences:  A006596 A006597 A006598 * A006600 A006601 A006602

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Rick L. Shepherd, Sep 07 2002

a(13) = 7349 from Jeppe Stig Nielsen, Mar 28 2014

STATUS

approved

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Last modified February 24 14:41 EST 2018. Contains 299623 sequences. (Running on oeis4.)