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A050565
Numbers k such that 79*2^k-1 is prime.
0
1, 3, 7, 15, 43, 57, 61, 75, 145, 217, 247, 2803, 3403, 4375, 5113, 9883, 14565, 17397, 65977, 82081, 92517, 214453, 248055, 369535, 969795
OFFSET
1,2
MATHEMATICA
Select[Range[1000], PrimeQ[79*2^# - 1] & ] (* Robert Price, Dec 22 2018 *)
PROG
(PARI) is(n)=ispseudoprime(79*2^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A230958 A146033 A147188 * A097111 A371914 A151401
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(25) from the Wilfrid Keller link by Robert Price, Dec 22 2018
STATUS
approved