The cluster correlation function and its richness dependence are determined from 1108 clusters of galaxies – the largest sample of clusters studied so far – found in 379 deg ^ { 2 } of Sloan Digital Sky Survey early data .
The results are compared with previous samples of optically and X-ray selected clusters .
The richness-dependent correlation function increases monotonically from an average correlation scale of \sim 12 h ^ { -1 } Mpc for poor clusters to \sim 25 h ^ { -1 } Mpc for the richer , more massive clusters with a mean separation of \sim 90 h ^ { -1 } Mpc .
X-ray selected clusters suggest slightly stronger correlations than optically selected clusters ( \sim 2- \sigma ) .
The results are compared with large-scale cosmological simulations .
The observed richness-dependent cluster correlation function is well represented by the standard flat LCDM model ( \Omega _ { m } \simeq 0.3 , h \simeq 0.7 ) , and is inconsistent with the considerably weaker correlations predicted by \Omega _ { m } = 1 models .
An analytic relation for the correlation scale versus cluster mean separation , r _ { 0 } - d , that best describes the observations and the LCDM prediction is r _ { 0 } \simeq 2.6 \sqrt { d } ( for d \simeq 20 - 90 h ^ { -1 } Mpc ) .
Data from the complete Sloan Digital Sky Survey , when available , will greatly enhance the accuracy of the results and allow a more precise determination of cosmological parameters .