The argument describes an algorithm that can be translated into code.
1/(1-x)^(2) at 0 is 1
(1/(1-x)^(2) - 1)/x = (1 - 1 + 2x - x^(2))/x = 2 - x at 0 is 2
(1/(1-x)^(2) - 1 - 2x)/x^(2) = ((1 - 1 + 2x - x^(2) - 2x + 4x^(2) - 2x^(3))/x^(2) = 3 - 2x at 0 is 3
and so on
If you take immortality, you also probably need to take healing. Being mortally wounded and unable to die sounds, uh, bad.