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A050538 Numbers n such that 25*2^n-1 is prime. 0
3, 9, 11, 17, 23, 35, 39, 75, 105, 107, 155, 161, 215, 225, 335, 635, 651, 687, 1479, 1515, 1953, 2435, 2963, 3671, 5979, 7551, 8091, 9791, 15015, 20897, 26279, 43371, 130407, 587585, 716769, 942563 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Ray Ballinger and Wilfrid Keller, List of primes k.2^n + 1 for k < 300
PROG
(PARI) is(n)=ispseudoprime(25*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A215816 A211864 A157139 * A062227 A111324 A107073
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

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Last modified March 28 12:26 EDT 2024. Contains 371254 sequences. (Running on oeis4.)