I've optimized the code. Hopping speed improved about 50% per core.
with 4 cores I've reached 850000 h/s.
Timing:
Case # time (sec)
50 148.46
51 120.88
52 189.33
53 204.99
54 674.51
55 441.58
56 945.33
57 1509.22
58 2685.02
59 2300.80
60 4389.98
61 2958.66
62 7802.91
63 10239.27