

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
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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



