I was wondering if there are closed formulas for the singularvalues of a partial Hankel matrix (by partial I mean $\ell<n$)

\begin{align*} H= \begin{bmatrix} c_1 & c_2 & \ldots & c_\ell \\ c_2 & c_3 & \ldots & c_{\ell+1} \\ c_3 & c_4 & \ldots & c_{\ell+2}\\ \vdots & \vdots & \ddots & \vdots\\ c_n & c_{n+1} &\ldots & c_{n+\ell-1} \end{bmatrix} \end{align*} What does it mean for this matrix to be low-rank?