  We study the optimal packing of hard spheres in an infinitely long cylinder,
using simulated annealing, and compare our results with the analogous problem
of packing disks on the unrolled surface of a cylinder. The densest structures
are described and tabulated in detail up to D/d=2.873 (ratio of cylinder and
sphere diameters). This extends previous computations into the range of
structures which include internal spheres that are not in contact with the
cylinder.
