Ok, so here goes nothing I have predict what this is in series form, the factorial in the numerator is really throwing me off. I only have to do the series for the first six terms. C0=C0 C2= -5/2 C0 C4= -3/4 C2 = (5x3)/(2x4) C0 C6= -1/6 C4 = -(5x3x1)/(2x4x6) C0 This is what I have so far, although I cannot completely find out the numerator: n is 0,1,2,3 C(2n)=[(-1)^n][???]/[(2n)!!] C0 or C(2n)=[(-1)^n][???]/[2^n x n!] C0 I cannot find out how to correctly represent the numerator. Can you guys give me any pointers?