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Numbers k such that 8^k + k^8 - 1 is prime.
1

%I #20 Jul 12 2018 11:33:43

%S 10,38,428,824,3902,4712,5596,29572

%N Numbers k such that 8^k + k^8 - 1 is prime.

%C a(9) > 10^5. _Robert Price_, Feb 25 2014

%t Select[Range[0, 4000],PrimeQ[8^# + #^8 - 1] &]

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

%Y Cf. A100357, A215434-A215446, A216375.

%K nonn,hard,more

%O 1,1

%A _Vincenzo Librandi_, Sep 09 2012

%E a(6)-a(8) from _Robert Price_, Feb 25 2014