The maximum number of halving lines and the rectilinear crossing number of Kn for n⩽27

For n⩽27 we present exact values for the maximum number h(n) of halving lines and of halving pseudolines, determined by n points in the plane. For this range of values of n we also present exact values of the rectilinear and the pseudolinear crossing numbers of the complete graph Kn. and are new for n∈{14,16,18,20,22,23,24,25,26,27}, h(n) is new for n∈{16,18,20,22,23,24,25,26,27}, and is new for n∈{20,22,23,24,25,26,27}.