A050552 Numbers k such that 53*2^k-1 is prime.

2, 6, 8, 42, 50, 62, 362, 488, 642, 846, 2870, 3042, 5096, 10556, 12642, 17850, 21710, 25230, 30392, 43122, 206970, 582078

Offset

1,1

Comments

582078 is also a member. - Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Links

Table of n, a(n) for n=1..22.

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[53*2^# - 1] & ] (* Robert Price, Dec 22 2018 *)

Prog

(PARI) is(n)=ispseudoprime(53*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A065953 A371832 A118211 * A105607 A098239 A140257

Adjacent sequences: A050549 A050550 A050551 * A050553 A050554 A050555

Keyword

hard,nonn,more

Author

N. J. A. Sloane, Dec 29 1999

Extensions

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

a(22) from the Wilfrid Keller link by Robert Price, Dec 22 2018

Status

approved