A006032 Numbers k such that (14^k - 1)/13 is prime.
3, 7, 19, 31, 41, 2687, 19697, 59693, 67421, 441697
Offset: 1
References
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Links
- Paul Bourdelais, A Generalized Repunit Conjecture
- H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
- H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930. [Annotated scanned copy]
- H. Lifchitz, Mersenne and Fermat primes field
Programs
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Mathematica
lst={};Do[If[PrimeQ[(14^n-1)/13], Print[n];AppendTo[lst, n]], {n, 10^5}];lst (* Vladimir Joseph Stephan Orlovsky, Aug 21 2008 *) -
PARI
is(n)=isprime((14^n - 1)/13) \\ Charles R Greathouse IV, Apr 29 2015
Extensions
One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
a(8) and a(9) correspond to probable primes discovered by Paul Bourdelais, Mar 01 2010
a(10) corresponds to a probable prime discovered by Paul Bourdelais, Dec 08 2014