  We study a 1-dimensional AKLT spin chain, consisting of spins $S$ in the bulk
and $S/2$ at both ends. The unique ground state of this AKLT model is described
by the Valence-Bond-Solid (VBS) state. We investigate the density matrix of a
contiguous block of bulk spins in this ground state. It is shown that the
density matrix is a projector onto a subspace of dimension $(S+1)^{2}$. This
subspace is described by non-zero eigenvalues and corresponding eigenvectors of
the density matrix. We prove that for large block the von Neumann entropy
coincides with Renyi entropy and is equal to $\ln(S+1)^{2}$.
