A050852 Numbers k such that 201*2^k-1 is prime.

1, 3, 9, 10, 14, 17, 21, 37, 57, 66, 70, 87, 94, 99, 123, 141, 147, 183, 207, 246, 269, 291, 313, 341, 361, 363, 615, 743, 1318, 1515, 1798, 2413, 2797, 3254, 3826, 7574, 11770, 15029, 21313, 21543, 21637, 30289, 31078, 37511, 70919, 80238, 81215, 81459

Offset

1,2

Links

Robert Price, Table of n, a(n) for n = 1..54

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

Mathematica

Select[Range[1000], PrimeQ[201*2^# - 1] & ] (* Robert Price, Dec 29 2018 *)

Prog

(PARI) is(n)=ispseudoprime(201*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A211185 A229269 A363954 * A066887 A030608 A118515

Adjacent sequences: A050849 A050850 A050851 * A050853 A050854 A050855

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(49)-a(54) from the Wilfrid Keller link by Robert Price, Dec 29 2018

Status

approved