The kissing number problem
The kissing number has no overlapping spheres. A kissing number is defined as the independent sphere which is touched. In lattice packing , the kissing number is the same, but arbitrary sphere packing is different because of the random shape of spheres. It is the maximum possible kissing number for n-dimensional spheres in (n + 1)-dimensional Euclidean space. In one dimension, the kissing number is 2 . In two dimensions, the kissing number is 6. This is isosceles. D=1 ⇒ 2 D=2 ⇒ 6 D=3 ⇒ 12 D=4 ⇒ 24 D=5 ⇒ 40 This is like exponential function.