  We study orthogonal polynomials with weight $\exp[-NV(x)]$, where
$V(x)=\sum_{k=1}^{d}a_{2k}x^{2k}/2k$ is a polynomial of order 2d. We derive the
generalised Freud's equations for $d=3$, 4 and 5 and using this obtain
$R_{\mu}=h_{\mu}/h_{\mu -1}$, where $h_{\mu}$ is the normalization constant for
the corresponding orthogonal polynomials. Moments of the density functions,
expressed in terms of $R_{\mu}$, are obtained using Freud's equation and using
this, explicit results of level densities as $N\rightarrow\infty$ are derived.
