A050862 Numbers n such that 221*2^n-1 is prime.

2, 6, 42, 354, 402, 914, 1562, 10382, 34986, 81042, 104846

Offset

1,1

Links

Table of n, a(n) for n=1..11.

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(221*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A074015 A074021 A364407 * A227250 A258969 A161632

Adjacent sequences: A050859 A050860 A050861 * A050863 A050864 A050865

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