A050901 Numbers k such that 285*2^k-1 is prime.

1, 7, 8, 12, 19, 23, 41, 44, 47, 62, 63, 79, 197, 293, 472, 788, 956, 1083, 1232, 1533, 1539, 1673, 2399, 2827, 2993, 3327, 3816, 4072, 4152, 4156, 4392, 4436, 4492, 5079, 5112, 5747, 7193, 7604, 7934, 8640, 9699, 10361, 10870, 12374, 16197, 18120, 29199

Offset

1,2

Links

Robert Price, Table of n, a(n) for n = 1..68

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

Maple

select(n->isprime(285*2^n-1), [$1..1000]); # Muniru A Asiru, Dec 30 2018

Mathematica

Select[Range[1000], PrimeQ[285*2^# - 1] & ] (* Robert Price, Dec 30 2018 *)

Prog

(PARI) is(n)=ispseudoprime(285*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A260628 A280999 A024706 * A105832 A059177 A065729

Adjacent sequences: A050898 A050899 A050900 * A050902 A050903 A050904

Keyword

hard,nonn

Author

N. J. A. Sloane, Dec 29 1999

Extensions

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

a(48)-a(68) from the Wilfrid Keller link by Robert Price, Dec 30 2018

Status

approved