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%I #10 Feb 20 2017 14:41:01
%S 2,6,12,362,884,9722
%N Numbers n such that 5^n - n is prime.
%C Farideh Firoozbakht reports that the only known prime of the form 5^n + n occurs when n = 7954 and that there are no others up to 20200. Oct 11 2003.
%C a(7) > 2*10^5. - _Robert Price_, Jan 16 2014
%t Do[ If[ PrimeQ[ 5^n - n ], Print[ n ] ], {n, 1, 13400} ]
%o (PARI) is(n)=ispseudoprime(5^n-n) \\ _Charles R Greathouse IV_, Feb 20 2017
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Nov 17 2000
%E The sixth term was found by _Farideh Firoozbakht_, who reports that there are no others up to 13400, Oct 11 2003