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 A057178 Numbers n such that (12^n + 1)/13 is a prime. 16
 5, 11, 109, 193, 1483, 11353, 21419, 21911, 24071, 106859, 139739 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS (12^1483+1)/13, a 1600-digit number, has now been certified prime with Primo. - Rick L. Shepherd, May 01 2002 LINKS 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=(12^n+1)/13; If[PrimeQ[p], AppendTo[lst, n]], {n, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Sep 29 2008 *) CROSSREFS Different from A056265. Sequence in context: A062652 A075706 A236509 * A056265 A041909 A041048 Adjacent sequences:  A057175 A057176 A057177 * A057179 A057180 A057181 KEYWORD nonn AUTHOR N. J. A. Sloane, Sep 15 2000 EXTENSIONS More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008 a(10) corresponds to a probable prime, discovered by Paul Bourdelais, Feb 08 2010 a(11) corresponds to a probable prime, discovered by Paul Bourdelais, Sep 21 2011 STATUS approved

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Last modified May 27 20:41 EDT 2017. Contains 287207 sequences.