%I #12 Jan 07 2015 18:14:58
%S 1,3,5,35,95,1323,24747
%N Numbers n such that 4^n - n is prime.
%C a(8) > 2*10^5. - _Robert Price_, Feb 11 2014
%t Do[ If[ PrimeQ[ 4^n - n ], Print[ n ] ], {n, 0, 3000} ]
%o (PARI) for(k=1,10^6,if(ispseudoprime(4^k-k),print1(k,", "))); /* _Joerg Arndt_, Apr 07 2013 */
%K nonn,more
%O 1,2
%A _Robert G. Wilson v_, Nov 16 2000
%E a(7) from _Robert Price_, Feb 11 2014