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A057177 Numbers n such that (11^n + 1)/12 is a prime. 15
5, 7, 179, 229, 439, 557, 6113, 223999, 327001, 2264611 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..10.

Paul Bourdelais, A Generalized Repunit Conjecture

J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.

H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.

H. Lifchitz, Mersenne and Fermat primes field

Eric Weisstein's World of Mathematics, Repunit

MATHEMATICA

lst={}; Do[p=(11^n+1)/12; If[PrimeQ[p], AppendTo[lst, n]], {n, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Sep 29 2008 *)

CROSSREFS

Sequence in context: A164372 A318088 A123536 * A297535 A211769 A265031

Adjacent sequences:  A057174 A057175 A057176 * A057178 A057179 A057180

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 15 2000

EXTENSIONS

a(8) corresponds to a probable prime discovered by Paul Bourdelais, Feb 12 2010

a(9) corresponds to a probable prime discovered by Paul Bourdelais, Sep 30 2013

a(10) by Paul Bourdelais, Jul 19 2021

STATUS

approved

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Last modified December 8 00:04 EST 2021. Contains 349590 sequences. (Running on oeis4.)