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A050894
Numbers n such that 271*2^n-1 is prime.
0
1, 7, 21, 55, 175, 235, 2289, 12419, 19917, 19971, 21979, 54007, 66241, 68757, 98595, 241211, 274509, 322971, 342349, 470529
OFFSET
1,2
PROG
(PARI) is(n)=ispseudoprime(271*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A146709 A146400 A146408 * A146464 A001354 A200930
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