A006033 Numbers n such that (15^n - 1)/14 is prime.
3, 43, 73, 487, 2579, 8741, 37441, 89009, 505117, 639833
Offset: 1
Examples
(15^3 - 1)/14 = 241, which is prime.
References
- Paulo Ribenboim, "The Book Of Prime Number Records"; published 1989 by Springer-Verlag; pages 350-354.
- N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Links
- P. Bourdelais, A Generalized Repunit Conjecture
- Harvey Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
- H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930. [Annotated scanned copy]
- Henri Lifchitz, Mersenne and Fermat primes field
- Index to primes in various ranges, form ((k+1)^n-1)/k
Programs
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Mathematica
lst={};Do[If[PrimeQ[(15^n-1)/14], Print[n];AppendTo[lst, n]], {n, 10^5}];lst (* Vladimir Joseph Stephan Orlovsky, Aug 21 2008 *) -
PARI
is(n)=ispseudoprime((15^n-1)/14) \\ Charles R Greathouse IV, Apr 29 2015
Extensions
a(7) from Julien Peter Benney (jpbenney(AT)ftml.net), Apr 27 2007
a(8) corresponds to a probable prime discovered by Paul Bourdelais, Mar 15 2010
a(9) corresponds to a probable prime discovered by Paul Bourdelais, Jan 14 2015
a(10) corresponds to a probable prime discovered by Paul Bourdelais, Apr 22 2019
Comments