%I
%S 0,6,522,178438
%N Numbers n such that 4*17^n+1 is prime.
%C For n>0, members of the sequence may only be of form 4k+2 (otherwise the expression is divisible by 3 or 5). Therefore members of the sequence are a subset of A005574 and are Generalized Fermat primes.
%H <a href="http://mathworld.wolfram.com/GeneralizedFermatNumber.html">Generalized Fermat number at MathWorld</a>
%e For a(2) = 6 we have 4*17^6+1 = 96550277, which is prime.
%t Do[ If[ PrimeQ[ 4*17^n+1], Print[ n ]], {n, 0, 10000}]
%o (PARI) is(n)=isprime(4*17^n+1) \\ _Charles R Greathouse IV_, May 15 2013
%K more,nonn
%O 1,2
%A _Serge Batalov_, Sep 04 2010
