OFFSET
1,1
LINKS
Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300
Wilfrid Keller, List of primes k.2^n - 1 for k < 300
Kosmaj, Riesel list k<300.
MATHEMATICA
Select[Range[1000], PrimeQ[209*2^# - 1] & ] (* Robert Price, Dec 29 2018 *)
PROG
(PARI) is(n)=ispseudoprime(209*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
hard,nonn,more
AUTHOR
N. J. A. Sloane, Dec 29 1999
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
a(16) from the Wilfrid Keller link by Robert Price, Dec 29 2018
STATUS
approved