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A050879
Numbers n such that 241*2^n-1 is prime.
0
11, 17, 19, 39, 69, 321, 653, 1109, 3819, 5729, 9659, 9911, 13217, 16707, 22307, 65107, 75419, 97587, 99667, 336197, 407709, 497679
OFFSET
1,1
PROG
(PARI) is(n)=ispseudoprime(241*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A230654 A226686 A217055 * A245622 A050669 A362083
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