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 A057178 Numbers k such that (12^k + 1)/13 is a prime. 16

%I

%S 5,11,109,193,1483,11353,21419,21911,24071,106859,139739,495953

%N Numbers k such that (12^k + 1)/13 is a prime.

%C (12^1483 + 1)/13, a 1600-digit number, has now been certified prime with Primo. - _Rick L. Shepherd_, May 01 2002

%H Paul Bourdelais, <a href="https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;417ab0d6.0906">A Generalized Repunit Conjecture</a>

%H J. Brillhart et al., <a href="http://dx.doi.org/10.1090/conm/022">Factorizations of b^n +- 1</a>, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.

%H H. Dubner and T. Granlund, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL3/DUBNER/dubner.html">Primes of the Form (b^n+1)/(b+1)</a>, J. Integer Sequences, 3 (2000), #P00.2.7.

%H H. Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Repunit.html">Repunit</a>

%t lst={};Do[p=(12^n+1)/13;If[PrimeQ[p], AppendTo[lst, n]], {n, 7!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Sep 29 2008 *)

%Y Different from A056265.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Sep 15 2000

%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008

%E a(10) corresponds to a probable prime, discovered by _Paul Bourdelais_, Feb 08 2010

%E a(11) corresponds to a probable prime, discovered by _Paul Bourdelais_, Sep 21 2011

%E a(12) corresponds to a probable prime, discovered by _Paul Bourdelais_, Nov 13 2018

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Last modified June 20 17:27 EDT 2019. Contains 324234 sequences. (Running on oeis4.)