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%I #2 Mar 31 2012 14:45:48
%S 2,8,24,42
%N Numbers n such that prime(n)^n-n is prime.
%C All terms are even. There is no further term up to 10000. So the prime
%C corresponding to the next term if it exists has more than 50200 digits.
%C 1 and 2 are the only known numbers n (up to 10000) such that prime(n)^n+n
%C is prime.
%e prime(2)^2-2=3^2-2=7 is prime, so 2 is in the sequence.
%t Do[If[PrimeQ[Prime[n]^n-n],Print[n]],{n,50000}]
%Y Cf. A000040.
%K nonn
%O 1,1
%A _Farideh Firoozbakht_, Dec 07 2009
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