A050878 Numbers n such that 239*2^n-1 is prime.

4, 92, 25780, 104956, 140116, 356300

Offset

1,1

Links

Table of n, a(n) for n=1..6.

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

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Kosmaj, Riesel list k<300.

Prog

(PARI) is(n)=ispseudoprime(239*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A221287 A177411 A219891 * A173362 A353089 A202899

Adjacent sequences: A050875 A050876 A050877 * A050879 A050880 A050881

Keyword

hard,nonn

Author

N. J. A. Sloane, Dec 29 1999

Extensions

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Status

approved