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A032403
Numbers k such that 107*2^k+1 is prime.
0
3, 7, 23, 27, 291, 303, 311, 479, 567, 3087, 18459, 33575, 43123, 58291, 155587, 173007, 414531, 1220391, 1337019, 2081775, 2401731
OFFSET
1,1
PROG
(PARI) is(n)=ispseudoprime(107*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A355075 A173878 A225264 * A072584 A262250 A139513
KEYWORD
nonn,hard
EXTENSIONS
Extended by Hugo Pfoertner, Jul 02 2003
a(16)-a(20) from http://www.prothsearch.com/riesel1.html by Robert Price, Dec 14 2018
a(21) from Jeppe Stig Nielsen, Apr 04 2020
STATUS
approved