

A006033


Numbers n such that (15^n  1)/14 is prime.
(Formerly M3150)


13




OFFSET

1,1


COMMENTS

8741 and 37441 are only probable primes.  Julien Peter Benney (jpbenney(AT)ftml.net), Apr 27 2007


REFERENCES

Paulo Ribenboim, "The Book Of Prime Number Records"; published 1989 by SpringerVerlag; pages 350354.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Table of n, a(n) for n=1..10.
P. Bourdelais, A Generalized Repunit Conjecture
Harvey Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927930.
H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927930. [Annotated scanned copy]
Henri Lifchitz, Mersenne and Fermat primes field
Index to primes in various ranges, form ((k+1)^n1)/k


EXAMPLE

(15^3  1)/14 = 241, which is prime.


MATHEMATICA

lst={}; Do[If[PrimeQ[(15^n1)/14], Print[n]; AppendTo[lst, n]], {n, 10^5}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 21 2008 *)


PROG

(PARI) is(n)=ispseudoprime((15^n1)/14) \\ Charles R Greathouse IV, Apr 29 2015


CROSSREFS

Cf. A059802, A062647, A003525.
Sequence in context: A139854 A194578 A185632 * A246994 A142184 A199348
Adjacent sequences: A006030 A006031 A006032 * A006034 A006035 A006036


KEYWORD

nonn,hard,more


AUTHOR

N. J. A. Sloane


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


STATUS

approved



