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A050842
Numbers k such that 181*2^k-1 is prime.
0
3, 5, 7, 9, 11, 17, 23, 31, 35, 43, 47, 83, 85, 99, 101, 195, 267, 281, 363, 391, 519, 623, 653, 673, 701, 1091, 1147, 1565, 3273, 3661, 3923, 4127, 4783, 5267, 5345, 5747, 6151, 6299, 7569, 9033, 11843, 14139, 14175, 15779, 21557, 32295, 49823, 60979, 65195, 132367, 133895, 186827, 212647
OFFSET
1,1
MATHEMATICA
Select[Range[1000], PrimeQ[181*2^# - 1] & ] (* Robert Price, Dec 29 2018 *)
PROG
(PARI) is(n)=ispseudoprime(181*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A322553 A302601 A064076 * A143447 A318777 A152484
KEYWORD
hard,nonn
AUTHOR
N. J. A. Sloane, Dec 29 1999
EXTENSIONS
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
a(49)-a(53) from the Wilfrid Keller link by Robert Price, Dec 29 2018
STATUS
approved