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A004064 Numbers n such that (12^n - 1)/11 is prime.
(Formerly M0744)
25
2, 3, 5, 19, 97, 109, 317, 353, 701, 9739, 14951, 37573, 46889 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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.

J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 109, p. 38, Ellipses, Paris 2008.

H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.

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.

H. Lifchitz, Mersenne and Fermat primes field

S. S. Wagstaff, Jr., The Cunningham Project

Eric Weisstein's World of Mathematics, Repunit.

MATHEMATICA

lst={}; Do[If[PrimeQ[(12^n-1)/11], Print[n]; AppendTo[lst, n]], {n, 10^5}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 21 2008 *)

CROSSREFS

Sequence in context: A235622 A235637 A028490 * A164061 A128363 A106047

Adjacent sequences:  A004061 A004062 A004063 * A004065 A004066 A004067

KEYWORD

nonn,hard,changed

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(11) from Paul Bourdelais, Aug 03 2007

One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008

a(13)=46889, discovered Sep 10 2008 by Paul Bourdelais, is a probable prime based on trial factoring to 10^13 and Fermat base 2 primality test. - Paul Bourdelais, Sep 11 2008

STATUS

approved

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Last modified November 26 17:58 EST 2014. Contains 250082 sequences.