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

Terms

a(0) =1a(1) =-2a(2) =1a(3) =-1a(4) =4a(5) =-5a(6) =3a(7) =-6a(8) =13a(9) =-13a(10) =12a(11) =-25a(12) =39a(13) =-38a(14) =49a(15) =-89a(16) =116a(17) =-125a(18) =187a(19) =-294a(20) =357a(21) =-437a(22) =668a(23) =-945a(24) =1151a(25) =-1542a(26) =2281a(27) =-3041a(28) =3844a(29) =-5365