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

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =1a(5) =-2a(6) =3a(7) =-4a(8) =6a(9) =-10a(10) =17a(11) =-28a(12) =45a(13) =-72a(14) =116a(15) =-188a(16) =305a(17) =-494a(18) =799a(19) =-1292a(20) =2090a(21) =-3382a(22) =5473a(23) =-8856a(24) =14329a(25) =-23184a(26) =37512a(27) =-60696a(28) =98209a(29) =-158906