A050894 Numbers n such that 271*2^n-1 is prime.

1, 7, 21, 55, 175, 235, 2289, 12419, 19917, 19971, 21979, 54007, 66241, 68757, 98595, 241211, 274509, 322971, 342349, 470529

Offset

1,2

Links

Table of n, a(n) for n=1..20.

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(271*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A146709 A146400 A146408 * A146464 A001354 A200930

Adjacent sequences: A050891 A050892 A050893 * A050895 A050896 A050897

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