I'm looking to evaluate the infinite sum of 1/(n-f)^2 where n is the index of summation from 1 to infinity and f is a constant between zero and one.

I really have no clue where to start on this. I've seen the summation evaluated to pi^2/6 if f=0 by using a Fourier transform of x^2, but I can't see how to adapt this for an arbitrary constant.

Any ideas or hints would be appreciated.