[math-fun] Sum of reciprocal integer powers = 3/5 ???

A few years ago I read in some math journal that a certain sum of reciprocal integer powers has an unexpectedly simple sum -- I think it was 3/5. But I can't find the article or a reference to this fact. So I don't know just which reciprocal integer powers are being summed (or whether 3/5 is right). Can anyone give me a pointer to this result? Thanks, Dan ________________________________________________________________________________________ It goes without saying that .