A050538 Numbers n such that 25*2^n-1 is prime.

3, 9, 11, 17, 23, 35, 39, 75, 105, 107, 155, 161, 215, 225, 335, 635, 651, 687, 1479, 1515, 1953, 2435, 2963, 3671, 5979, 7551, 8091, 9791, 15015, 20897, 26279, 43371, 130407, 587585, 716769, 942563

Offset

1,1

Links

Table of n, a(n) for n=1..36.

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(25*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A215816 A211864 A157139 * A062227 A111324 A107073

Adjacent sequences: A050535 A050536 A050537 * A050539 A050540 A050541

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