A050590 Numbers k such that 129*2^k-1 is prime.

1, 3, 4, 5, 8, 9, 12, 16, 28, 51, 56, 59, 72, 73, 88, 93, 105, 148, 165, 292, 368, 445, 635, 771, 773, 940, 1173, 1965, 2661, 3092, 5001, 5091, 8741, 9773, 13960, 15328, 19408, 19911, 21228, 34876, 37341, 38564, 39055, 39152, 45395, 68825, 72360, 78365, 126303, 130240, 150808, 214985

Offset

1,2

Links

Table of n, a(n) for n=1..52.

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[129*2^# - 1] & ] (* Robert Price, Dec 23 2018 *)

Prog

(PARI) is(n)=ispseudoprime(129*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A316976 A256173 A050070 * A329856 A327984 A066906

Adjacent sequences: A050587 A050588 A050589 * A050591 A050592 A050593

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(52) from the Wilfrid Keller link by Robert Price, Dec 23 2018

Status

approved