login
A032493
Numbers k such that 233*2^k+1 is prime.
0
1, 5, 9, 13, 17, 25, 33, 53, 57, 77, 521, 593, 609, 845, 917, 985, 1321, 1801, 3565, 4953, 5137, 13193, 14173, 15517, 15629, 21853, 22009, 24625, 40041, 47797, 50257, 52433, 114881, 174785, 294485, 331321, 355945, 517373, 768241, 1649741, 1662513, 2022801
OFFSET
1,2
MATHEMATICA
Select[Range[1000], PrimeQ[233*2^# + 1] & ] (* Robert Price, Dec 19 2018 *)
PROG
(PARI) is(n)=ispseudoprime(233*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A057653 A085759 A314700 * A362256 A349538 A334524
KEYWORD
nonn,hard
AUTHOR
EXTENSIONS
a(34)-a(41) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 19 2018
a(42) from Jeppe Stig Nielsen, May 31 2020
STATUS
approved