  We present data of Monte Carlo simulations for monodisperse linear polymer
chains in dense melts with degrees of polymerization between N=16 and N=512.
The aim of this study is to investigate the crossover from Rouse-like dynamics
for short chains to reptation-like dynamics for long chains. To address this
problem we calculate a variety of different quantities: standard mean-square
displacements of inner monomers and of the chain's center of mass, the recently
proposed cubic invariant, persistence of bond-vector orientation with time, and
the auto-correlation functions of the bond vector, the end-to-end vector and
the Rouse modes. This analysis reveals that the crossover from non- to
entangled dynamics is very protracted. Only the largest chain length N=512,
which is about 13 times larger than the entanglement length, shows evidence for
reptation.
