On Contact Numbers of Finite Lattice Sphere Packings and the Maximal   Coordination of Monatomic Crystals
  We algorithmically characterize the maximal contact number problem for finite congruent lattice sphere packings in $\mathbb{R}^d$ and show that in $\mathbb{R}^3$ this problem is equivalent to determining the maximal coordination of a monatomic crystal. 
Samuel Reid
math.MG