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A291853
Numbers n such that (3^n - (-2)^n)/5 is prime.
0
3, 4, 7, 11, 83, 149, 223, 599, 647, 1373, 8423
OFFSET
1,1
COMMENTS
a(12) > 65535. Presumably, a(12) = 149497 and a(13) = 388897.
EXAMPLE
4 is in this sequence because (3^4 - (-2)^4)/5 = 13 is prime.
MATHEMATICA
Select[Range[2000], PrimeQ[(3^# - (-2)^#)/5] &] (* Michael De Vlieger, Dec 09 2017 *)
PROG
(Magma) [n: n in [1..1000] | IsPrimePower((3^n-(-2)^n) div 5)];
CROSSREFS
Supersequence A057469.
Cf. A107036 (numbers n such that (2^n-(-1)^n)/3 is prime).
Sequence in context: A042655 A041901 A111518 * A041153 A041781 A042893
KEYWORD
nonn,more
AUTHOR
STATUS
approved