A050581 Numbers k such that 111*2^k-1 is prime.

2, 3, 6, 7, 21, 22, 23, 26, 29, 31, 58, 59, 67, 78, 83, 146, 159, 162, 165, 183, 262, 511, 718, 815, 1181, 1255, 1422, 1506, 1541, 1734, 2213, 3623, 4223, 4551, 5741, 5878, 6599, 11349, 12102, 17811, 19798, 20559, 26887, 32499, 40626, 43151, 49194, 52859, 98462, 101962, 126754, 133062, 147346, 217034, 279227, 345867, 362466, 378595, 448102, 520923, 602565, 656935, 791502

Offset

1,1

Comments

Also in the sequence: 959671. - Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Links

Table of n, a(n) for n=1..63.

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

Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime

Kosmaj, Riesel list k<300.

Prog

(PARI) is(n)=ispseudoprime(111*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A328023 A265481 A023785 * A352934 A073317 A371293

Adjacent sequences: A050578 A050579 A050580 * A050582 A050583 A050584

Keyword

hard,nonn

Author

N. J. A. Sloane, Dec 29 1999

Extensions

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

Status

approved