Quote:
Originally Posted by carpetpool

That sounds correct. In fact it seems the Gaussian Mersenne norms includes a bit more candidates, namely 2^{2k+1} ± 2^{k+1} + 1 where the sign of the middle term is picked such that the candidate is not divisible by 5. You can fix the sign, then you will get "half" of the Gaussian Mersenne norms. /JeppeSN