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A032457
Numbers k such that 161*2^k+1 is prime.
0
3, 5, 11, 13, 51, 53, 63, 71, 103, 179, 205, 267, 351, 589, 719, 1453, 3703, 7935, 10851, 15151, 16013, 20319, 65475, 66083, 105269, 181059, 186347, 319875, 1057743, 1668927, 1754223, 2142431
OFFSET
1,1
MATHEMATICA
Select[Range[1000], PrimeQ[161*2^# + 1] & ] (* Robert Price, Dec 18 2018 *)
PROG
(PARI) is(n)=ispseudoprime(161*2^n+1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A147568 A359303 A006794 * A122564 A162876 A162875
KEYWORD
nonn,hard,more
AUTHOR
EXTENSIONS
a(25)-a(31) from the Ray Ballinger and Wilfrid Keller link by Robert Price, Dec 18 2018
a(32) from Jeppe Stig Nielsen, May 30 2020
STATUS
approved