%I #9 Jun 13 2017 12:38:59

%S 9,15,33,51,57,99,111,117,135,141,183,189,195,267,309,327,345,369,387,

%T 399,405,411,429,441,447,495,513,525,537,567,603,609,645,663,681,687,

%U 705,723,777,783,789,807,813,831,861,897,909,915,981

%N Numbers n such that 5*n^2 + 4 is prime.

%e If n=399 then 5*n^2 + 4 = 796009 (prime).

%t Select[Range[1000], PrimeQ[5*#^2 + 4] &] (* _Stefan Steinerberger_, Feb 26 2006 *)

%o (PARI) is(n)=isprime(5*n^2+4) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,easy

%O 1,1

%A _Parthasarathy Nambi_, Oct 18 2005

%E More terms from _Stefan Steinerberger_, Feb 26 2006