Expansion of (1-x)/(1+x-x^2+x^3).

Terms

a(0) =1a(1) =-2a(2) =3a(3) =-6a(4) =11a(5) =-20a(6) =37a(7) =-68a(8) =125a(9) =-230a(10) =423a(11) =-778a(12) =1431a(13) =-2632a(14) =4841a(15) =-8904a(16) =16377a(17) =-30122a(18) =55403a(19) =-101902a(20) =187427a(21) =-344732a(22) =634061a(23) =-1166220a(24) =2145013a(25) =-3945294a(26) =7256527a(27) =-13346834a(28) =24548655a(29) =-45152016