[ttoinou]

i=0+1*i =0+1*(0+1*(0+1*(0+1*(0+1*(0+1*( ...*

[chongli]

... = -2 - (-3) = -1 - (-2) = 0 - (-1) = 1 - 0 = 1 = 2 - 1 = 3 - 2 = 4 - 3 = 5 - 4 = ...