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A323040
Numbers k such that 391*2^k+1 is prime.
0
4, 20, 28, 40, 88, 92, 328, 1052, 1420, 2888, 3944, 5888, 22544, 154912, 716668
OFFSET
1,1
MATHEMATICA
Select[Range[1000], PrimeQ[391*2^# + 1] &] (* Robert Price, Jan 03 2019 *)
CROSSREFS
Sequence in context: A097251 A202070 A198831 * A259755 A317249 A181433
KEYWORD
nonn,more,hard
AUTHOR
Robert Price, Jan 03 2019
STATUS
approved