%I

%S 0,1,819,1449,1677,13319

%N Numbers n such that 2*41^n + 1 is prime.

%C Primes found and proved by PrimeForm. No more terms up to 30000.

%o (PARI) is(n)=ispseudoprime(2*41^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017

%Y Cf. A141802.

%K hard,nonn

%O 1,3

%A _Rick L. Shepherd_, Aug 02 2008