A050892 Numbers k such that 267*2^k-1 is prime.

4, 5, 8, 14, 16, 17, 20, 26, 28, 34, 40, 44, 53, 58, 74, 80, 86, 94, 128, 130, 140, 149, 178, 365, 448, 878, 920, 1217, 2417, 3400, 3725, 3934, 4454, 5276, 7360, 9544, 11860, 16270, 32038, 37468, 116537, 117358, 119006, 147838, 198536, 211358, 216137, 238670, 287537

Offset

1,1

Links

Table of n, a(n) for n=1..49.

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[267*2^# - 1] & ] (* Robert Price, Dec 29 2018 *)

Prog

(PARI) is(n)=ispseudoprime(267*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A019526 A242014 A145488 * A347880 A274167 A145265

Adjacent sequences: A050889 A050890 A050891 * A050893 A050894 A050895

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

Status

approved