On the density of some special primes

We show, under the Generalized Riemann Hypothesis, that a certain set of primes which is of importance for the theory of pseudorandom sequences is of positive relative density. We also use an unconditional result of H. Mikawa, which in turn is based on the results of E. Bombieri, J. B. Friedlander and H. Iwaniec on primes in arithmetic progressions, which go beyond the range of the Generalized Riemann Hypothesis.7 page(s