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A032498
Numbers k such that 243*2^k+1 is prime.
1
1, 4, 12, 13, 18, 24, 49, 64, 78, 144, 148, 204, 258, 453, 796, 1309, 1612, 1812, 3873, 4348, 6354, 7996, 8536, 10128, 11289, 29544, 32773, 123114, 130998, 153417, 168093, 241602, 487938, 495732, 555984, 997537, 1177629, 1284429, 1516368, 1742689, 2685873
OFFSET
1,2
MATHEMATICA
Select[Range[1000], PrimeQ[243*2^# + 1] & ] (* Robert Price, Dec 20 2018 *)
PROG
(PARI) is(n)=ispseudoprime(243*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A103053 A087760 A237279 * A377048 A144613 A031330
KEYWORD
nonn,hard
AUTHOR
EXTENSIONS
a(31)-a(40) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 20 2018
a(41) (and b-file) from Jeppe Stig Nielsen, Jan 18 2020
STATUS
approved