[seqfan] A061421

[юрий герасимов]

Dear SegFans, 
If 
A061421  Primes of the form 2^n + n + 1 : 2, 7, 71, 110427941548649020598956093796432407239217743554726184882600387580788973, a(5) = 2^1884 + 1884 + 1,.., 
these
A_____?   Primes of the form 4^n - n - 1 : 2, 13, 251, 4294967279, a(5) = ?
Regards, 
Juri-Stepan Gerasimov.