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A050848 Numbers k such that 193*2^k-1 is prime. 0
3, 15, 27, 63, 87, 135, 543, 1383, 1455, 7767, 18543, 22143, 40967, 198719, 405483, 439107, 880287 (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
MATHEMATICA
Select[Range[1000], PrimeQ[193*2^# - 1] & ] (* Robert Price, Dec 29 2018 *)
PROG
(PARI) is(n)=ispseudoprime(193*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A147041 A347536 A002259 * A077785 A222291 A015646
KEYWORD
hard,nonn,more
AUTHOR
N. J. A. Sloane, Dec 29 1999
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
a(17) from the Wilfrid Keller link by Robert Price, Dec 29 2018
STATUS
approved

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Last modified May 27 13:56 EDT 2024. Contains 372861 sequences. (Running on oeis4.)