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A317887
Numbers k such that 4^k - 3^k + 2^k is prime.
0
1, 2, 4, 18, 56, 60, 88, 1288, 1784, 3406, 9250, 11968, 36216, 57206
OFFSET
1,2
COMMENTS
1 is the only odd number in this sequence.
a(15) > 65432.
EXAMPLE
4^2 - 3^2 + 2^2 = 16 - 9 + 4 = 11 is prime.
MATHEMATICA
Select[Range[0, 5000], PrimeQ[4^# - 3^# + 2^#] &]
PROG
(PARI) for(n=1, 5000, if(ispseudoprime(4^n-3^n+2^n), print1(n, ", ")))
CROSSREFS
Sequence in context: A318249 A093045 A330432 * A083694 A179040 A241685
KEYWORD
nonn,more
AUTHOR
Jinyuan Wang, Aug 09 2018
EXTENSIONS
a(13)-a(14) from Giovanni Resta, Aug 10 2018
STATUS
approved