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A271884
Numbers n such that 4^n-3^(n-1) is prime.
6
1, 2, 4, 6, 10, 12, 30, 42, 54, 166, 264, 886, 1476, 8412, 9576, 12426, 24076
OFFSET
1,2
COMMENTS
a(18) > 10^5.
EXAMPLE
4 is a member since 4^4 - 3^3 = 256 - 27 = 229 which is a prime number.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[4^# - 3^(# - 1)] &]
PROG
(PARI) lista(nn) = for(n=1, nn, if(ispseudoprime(4^n-3^(n-1)), print1(n, ", "))); \\ Altug Alkan, Apr 16 2016
KEYWORD
nonn,more
AUTHOR
Robert Price, Apr 16 2016
STATUS
approved