A006034 Numbers n such that (17^n-1)/16 is prime. (Formerly M2415)

3, 5, 7, 11, 47, 71, 419, 4799, 35149, 54919, 74509, 1990523

Offset

1,1

Comments

No others for any n less than 8447. - Julien Peter Benney (jpbenney(AT)ftml.net), Aug 15 2004

References

Ribenboim, Paulo; "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

Table of n, a(n) for n=1..12.

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

Mathematica

lst={}; Do[If[PrimeQ[(17^n-1)/16], Print[n]; AppendTo[lst, n]], {n, 10^5}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 21 2008 *)

Prog

(PARI) is(n)=isprime((17^n-1)/16) \\ Charles R Greathouse IV, Apr 28 2015

Crossrefs

Sequence in context: A242944 A137355 A147143 * A288716 A083840 A088051

Adjacent sequences: A006031 A006032 A006033 * A006035 A006036 A006037

Keyword

hard,nonn,more

Author

N. J. A. Sloane

Extensions

a(9)=35149 & a(10)=54919 are probable primes discovered by Paul Bourdelais, Mar 08 2010

a(11)=74509 is a probable prime discovered by Paul Bourdelais, Mar 10 2010

a(12)=1990523 corresponds to a probable prime discovered by Paul Bourdelais, Aug 03 2020

Status

approved