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A032499
Numbers k such that 245*2^k+1 is prime.
0
1, 5, 9, 25, 69, 73, 99, 153, 163, 223, 273, 279, 331, 439, 445, 595, 601, 1189, 2311, 3523, 3773, 5369, 6349, 8743, 14083, 25225, 25371, 37773, 60615, 123471, 136993, 225185, 242925, 251025, 275419, 354079, 441021, 458995, 930031, 2748663
OFFSET
1,2
MATHEMATICA
Select[Range[1000], PrimeQ[245*2^# + 1] & ] (* Robert Price, Dec 20 2018 *)
PROG
(PARI) is(n)=ispseudoprime(245*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A301960 A050359 A062812 * A112084 A038251 A034498
KEYWORD
nonn,hard,more
AUTHOR
EXTENSIONS
a(32)-a(39) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018
a(40) from Jeppe Stig Nielsen, Feb 25 2020
STATUS
approved