Take a trip over here and explain to me what is meant by taking the double factorial of [itex]-1[/itex]. If you try to let [itex]N = 1[/itex] in the remainder formula, you wind up having to take [itex](2(0) - 1)!! = (-1)!![/itex], right? This strikes me as a typo; should it be changed? If so, to what?