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A050885
Numbers n such that 253*2^n-1 is prime.
0
71, 1007, 27623, 1722623
OFFSET
1,1
PROG
(PARI) is(n)=ispseudoprime(253*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A253683 A210699 A346023 * A200909 A175215 A231414
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