%I #6 Nov 23 2023 12:51:43

%S 0,1,5,71,311

%N Numbers n such that 1+9*10^n+100^n is prime.

%C No more terms up to n=7200.

%t Select[Range[0,320],PrimeQ[1+9 10^#+100^#]&] (* _Harvey P. Dale_, Nov 23 2023 *)

%o (PARI) is(n)=ispseudoprime(1+9*10^n+100^n) \\ _Charles R Greathouse IV_, Jun 13 2017

%K more,nonn

%O 1,3

%A _Jason Earls_, Dec 11 2009