The number of smallest knots on the cubic lattice (Q1897020)

Polygons on the cubic lattice are piecewise linear simple closed curves such that each linear piece is of unit length and its vertices are on the cubic lattice. Such polygons are used to simulate the behavior of (thick) random closed curves found in models from chemistry and physics. Knotting of such polygons is an interesting problem. It has been shown that a polygon on the cubic lattice needs at least 24 edges to form a knot. It is shown that the only knots one can obtain with 24 edges are the trefoils. Furthermore, by classifying the projections of the polygons on a plane, we are able to enumerate all possible knotted polygons on the cubic lattice with 24 edges. The number of such unrooted knots on the cubic lattice is 3496.