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%I #27 Jul 04 2021 09:02:23
%S 5,11,103,227,1637,9677,41597
%N Numbers k such that 86^k - 85^k is prime.
%C Terms greater than 1000 are often only strong pseudoprimes.
%C All terms are prime. - _Robert Price_, Apr 14 2014
%C a(8) > 10^5. - _Robert Price_, Apr 14 2015
%t Select[Range[0, 300], If[PrimeQ[#], PrimeQ[86^# - 85^#]] &] (* _Robert Price_, Apr 14 2015 *)
%o (PARI) is(n)=ispseudoprime(86^n-85^n) \\ _Charles R Greathouse IV_, Jun 12 2017
%Y Cf. A000043, A057468, A059801, A059802, A062572-A062666, A215536 (primes 87^n - 86^n).
%K nonn,hard
%O 1,1
%A _Mike Oakes_, May 18 2001, May 19 2001
%E a(7) from _Robert Price_ (computer run by Adam Marciniec), Apr 14 2015