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A003306 Numbers n such that 2*3^n + 1 is prime.
(Formerly M0951)
9
0, 1, 2, 4, 5, 6, 9, 16, 17, 30, 54, 57, 60, 65, 132, 180, 320, 696, 782, 822, 897, 1252, 1454, 4217, 5480, 6225, 7842, 12096, 13782, 17720, 43956, 64822, 82780, 105106, 152529, 165896, 191814, 529680, 1074726, 1086112, 1175232 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

REFERENCES

Wilfrid Keller and Jorg Richstein, Solutions of the congruence a^(p-1) = 1 (mod p^r), Math. Comp., Vol. 74 (2005), 927-936.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

H. C. Williams and C. R. Zarnke, Some prime numbers of the forms 2*3^n+1 and 2*3^n-1, Math. Comp., 26 (1972), 995-998.

LINKS

C. K. Caldwell, The Prime Pages

MATHEMATICA

lst={}; Do[If[PrimeQ[2*3^n+1], AppendTo[lst, n]], {n, 0, 10^4}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 19 2008]

CROSSREFS

Cf. A056802 (n such that 2*9^n + 1 is prime).

Cf. A111974 (primes of the form 2*3^n+1), A003307 (n such that 2*3^n-1 is prime).

Sequence in context: A073894 A056635 A163116 * A136585 A122721 A014224

Adjacent sequences:  A003303 A003304 A003305 * A003307 A003308 A003309

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), caldwell(AT)UTM.Edu (Chris Caldwell)

EXTENSIONS

More terms from T. D. Noe (noe(AT)sspectra.com), Aug 24 2005

More terms from David Broadhurst (D.Broadhurst(AT)open.ac.uk), Feb 14 2010

Another term from David Broadhurst (D.Broadhurst(AT)open.ac.uk), Feb 22 2010

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Last modified February 15 08:20 EST 2012. Contains 205729 sequences.