A050884 Numbers n such that 251*2^n-1 is prime.

6, 110, 1302, 4598, 74030, 359790

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

Kosmaj, Riesel list k<300.

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

Prog

(PARI) is(n)=ispseudoprime(251*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A217987 A119814 A227443 * A156554 A197325 A197978

Adjacent sequences: A050881 A050882 A050883 * A050885 A050886 A050887

Keyword

hard,nonn

Author

N. J. A. Sloane, Dec 29 1999

Extensions

359790 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Status

approved