Fourier series of a pulse

can anyone tell me how to find the peak amplitudes of a pulse?

I have an equation which I cant get to work (assuming its right)

I have:

Vn = (2)x(Vp)x(tau) / (T) X (sin)x(n)x(pi)x(tau/T) /(n)x(pi)x(tau/T)

where

Vp = 1
tau = 0.4ms
T = 2ms
n = 1 - 10

I have the values for n = 1 - 10

1 = 0.374V
2 = 0.303
3 = 0.202
4 = 0.094 etc

I tried putting this in a calculator and I dont get these answers.