I have this example of a correlation matrix in my notes:
$$R = E[XX^T]$$ $$n = 3, E[X_i X_{j}^*] = 2^{|i-j|}$$ $$R = \left[ \begin{matrix} 1 & 0.5 & 0.25 \\ 0.5 & 1 & 0.5 \\ 0.25 & 0.5 & 1 \\ \end{matrix} \right] $$
It seems as if the off-diagonal entries are $\frac{1}{2^{|i-j|}}$ instead of the given $2^{|i-j|}$.