A138956 - OEIS

%I #5 Nov 21 2013 12:49:20

%S 461,10501,2149818248341,20728082811027490541,

%T 481868222983777875077033646523111996342381,

%U 63774650109719491827977851592475862662743267652837460857617262084586443004114519194264814815101

%N Primes of the form (4^n + 5^n)/9.

%t a={}; Do[p=(4^n+5^n)/9; If[PrimeQ[p], AppendTo[a, p]], {n, 1, 12^2}];a

%t Select[Table[(4^n+5^n)/9,{n,160}],PrimeQ] (* _Harvey P. Dale_, Oct 22 2011 *)

%Y Cf. A128335.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, May 16 2008