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Numbers n such that 8^n-7^(n-1) is prime.
1

%I #7 Jun 13 2017 10:36:46

%S 1,3,5,29,41,83,471,725,1277,10271,15069,97731

%N Numbers n such that 8^n-7^(n-1) is prime.

%C a(13) > 10^5.

%e 5 is a member since 8^5 - 7^4 = 32768 - 2401 = 30367 which is a prime number.

%t Select[Range[0, 100000], PrimeQ[8^# - 7^(# - 1)] &]

%o (PARI) is(n)=ispseudoprime(8^n-7^(n-1)) \\ _Charles R Greathouse IV_, Jun 13 2017

%Y Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883, A271884.

%K nonn,more

%O 1,2

%A _Robert Price_, Apr 26 2016