对于n=3,-1、-1、-1,1,1的20种不同排列导致7个能级(符号反向距离之和):
{0,0,0,1,1,1},{1,1,1,0,0,0}: 13/10
{0,0,1,0,1,1},{1,1,0,1,0,0}: -41/30
{0,0,1,1,0,1},{0,1,0,0,1,1},{1,0,1,1,0,0},{1,1,0,0,1,0}: -56/30
{0,0,1,1,1,0},{0,1,1,1,0,0},{1,0,0,0,1,1},{1,1,0,0,0,1}: -8/10
{0,1,0,1,0,1},{1,0,1,0,1,0}: -37/10
{0,1,0,1,1,0},{0,1,1,0,1,0},{1,0,0,1,0,1},{1,0,1,0,0,1}: -89/30
{0,1,1,0,0,1},{1,0,0,1,1,0}: -71/30
所以重数是4*2+3*4=20=二项式(6,3)。