

A006035


Numbers n such that (19^n1)/18 is prime.
(Formerly M5072)


12



19, 31, 47, 59, 61, 107, 337, 1061, 9511, 22051, 209359
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OFFSET

1,1


COMMENTS

No others less than 8011.  Julien Peter Benney (jpbenney(AT)ftml.net), Aug 15 2004
a(9) = 9511 was found by Richard Fischer on Dec 15 2004.  Alexander Adamchuk, Feb 11 2007


REFERENCES

Ribenboim, Paulo; "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..11.
Paul Bourdelais, A Generalized Repunit Conjecture.  Paul Bourdelais, Aug 27 2010
H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927930.
H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927930. [Annotated scanned copy]
H. Lifchitz, Mersenne and Fermat primes field
Index to primes in various ranges, form ((k+1)^n1)/k


MATHEMATICA

lst={}; Do[If[PrimeQ[(19^n1)/18], Print[n]; AppendTo[lst, n]], {n, 10^5}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 21 2008 *)


PROG

(PARI) is(n)=isprime((19^n1)/18) \\ Charles R Greathouse IV, Apr 28 2015


CROSSREFS

Sequence in context: A096787 A104006 A117065 * A104485 A276569 A276447
Adjacent sequences: A006032 A006033 A006034 * A006036 A006037 A006038


KEYWORD

nonn,more


AUTHOR

N. J. A. Sloane


EXTENSIONS

One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
a(11)=209359 corresponds to a probable prime discovered by Paul Bourdelais, Aug 27 2010


STATUS

approved



