%I

%S 23,443,194483

%N Primes of the form 21^(2^n) + 2.

%C a(n) is congruent 3 mod 4.

%C The next term (if it exists) corresponds to some n>23, so it has more than 11 million digits. [R. J. Mathar, Aug 23 2010]

%Y Cf. A057726, A152589.

%K nonn,bref

%O 1,1

%A _Giovanni Teofilatto_, Mar 14 2010

%E Entries checked. - _R. J. Mathar_, Aug 23 2010