  We investigate the distribution of clusters of galaxies and determine the
cluster correlation function and power spectrum. Clusters of galaxies located
in rich superclusters with at least 8 members form a quasiregular network of
superclusters and voids. The correlation function of clusters in rich
superclusters is oscillating with a period of 120 Mpc (for Hubble constant
h=1), the power spectrum for the whole cluster sample has a peak at the
corresponding wavelength. The power index on small wavelengths is n=-1.8, on
large wavelengths the power index is within observational errors compatible
with the Harrison-Zeldovich index n=1. The observed spectrum is compared with
the spectrum of the standard CDM model, the probability that the observed
spectrum is a random realisation of the CDM-type model is estimated to be not
larger than one in million.
