Negative correlations in the distribution of prime numbers are found to
display a scale invariance. This occurs in conjunction with a nonstationary
behavior. We compare the prime number series to a type of fractional Brownian
motion which incorporates both the scale invariance and the nonstationary
behavior. Interesting discrepancies remain. The scale invariance also appears
to imply the Riemann hypothesis and we study the use of the former as a test of
the latter.Comment: 13 pages, 8 figures, version to appear in J. Phys.