Expansion of ((1+x)^3 - x^3)/((1+x)^5 - x^5).

Terms

a(0) =1a(1) =-2a(2) =3a(3) =-5a(4) =10a(5) =-20a(6) =35a(7) =-50a(8) =50a(9) =0a(10) =-175a(11) =625a(12) =-1625a(13) =3625a(14) =-7250a(15) =13125a(16) =-21250a(17) =29375a(18) =-29375a(19) =0a(20) =106250a(21) =-384375a(22) =1006250a(23) =-2250000a(24) =4500000a(25) =-8140625a(26) =13171875a(27) =-18203125a(28) =18203125a(29) =0