Fig. 3.

Computational results: (a), (b), and (c) are results with $N={10}^9,{10}^8,{10}^7$and $p=22$; (d), (e), and (f) are results with $N={10}^9,{10}^8,{10}^7$and $p=14$; (g), (h), and (i) are results with $N={10}^9,{10}^8,{10}^7$and $p=7$.