OFFSET
1,2
LINKS
Robert Price, Table of n, a(n) for n = 1..70
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[255*2^# - 1] & ] (* Robert Price, Dec 29 2018 *)
PROG
(PARI) is(n)=ispseudoprime(255*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
N. J. A. Sloane, Dec 29 1999
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
a(48)-a(70) from the Wilfrid Keller link by Robert Price, Dec 29 2018
STATUS
approved