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
MATHEMATICA
Select[Range[5*10^3], PrimeQ[277*2^# + 1] &] (* G. C. Greubel, May 24 2018 *)
PROG
(PARI) is(n)=ispseudoprime(277*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
(Magma) [n: n in [1..300] | IsPrime(277*2^n+1)]; // G. C. Greubel, May 24 2018
CROSSREFS
KEYWORD
hard,nonn,more
AUTHOR
N. J. A. Sloane, Dec 29 1999
EXTENSIONS
a(31)-a(39) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018
a(40) from Jeppe Stig Nielsen, Apr 04 2020
STATUS
approved