(2,1/2,1)
0 1 1*1
1 0 1*1
1 1 1*1
0 0 1*1
=0.50
2*1/4


(2,1/20,1)
0 1 19*1
1 0 1*19
1 1 1*1
0 0 19*19
=0.095
2*19/400