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A323149
Numbers k such that 441*2^k+1 is prime.
1
1, 3, 4, 13, 17, 21, 47, 76, 91, 137, 167, 181, 211, 347, 353, 407, 479, 553, 591, 747, 981, 1407, 3009, 3127, 6483, 10269, 17427, 21181, 24349, 36081, 54843, 56607, 64369, 64917, 66583, 79719, 83187, 109149, 133580, 137788, 141836, 145604, 146909, 181439
OFFSET
1,2
COMMENTS
The associated primes are: 883, 3529, 7057, 3612673, ... - Vincenzo Librandi, Jan 06 2019
When k is even, the associated prime is of form B^2 + 1. - Jeppe Stig Nielsen, Dec 27 2019
LINKS
MAPLE
select(k->isprime(441*2^k+1), [$1..1000]); # Muniru A Asiru, Jan 05 2019
MATHEMATICA
Select[Range[1000], PrimeQ[441*2^# + 1] &]
PROG
(Magma) [n: n in [1..5000] | IsPrime(441*2^n+1)]; // Vincenzo Librandi, Jan 06 2019
CROSSREFS
Sequence in context: A057570 A024853 A023857 * A291250 A205901 A302392
KEYWORD
nonn,hard
AUTHOR
Robert Price, Jan 05 2019
STATUS
approved