A050618 Numbers k such that 153*2^k-1 is prime.

3, 4, 6, 7, 10, 11, 12, 19, 20, 22, 23, 39, 66, 106, 120, 124, 151, 312, 411, 447, 474, 507, 574, 671, 787, 826, 979, 1690, 1954, 2047, 3003, 4323, 4426, 5903, 6267, 6846, 14550, 17470, 21520, 31711, 36724, 45291, 45654, 51778, 55420, 63439, 68451, 78423, 109696, 125128, 130710, 169836, 192900, 195028, 383083, 545716

Offset

1,1

Links

Table of n, a(n) for n=1..56.

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[153*2^# - 1] & ] (* Robert Price, Dec 23 2018 *)

Prog

(PARI) is(n)=ispseudoprime(153*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A135215 A092494 A274429 * A093579 A347752 A060832

Adjacent sequences: A050615 A050616 A050617 * A050619 A050620 A050621

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

Status

approved