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

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =10a(6) =19a(7) =33a(8) =61a(9) =108a(10) =197a(11) =352a(12) =638a(13) =1145a(14) =2069a(15) =3721a(16) =6714a(17) =12087a(18) =21794a(19) =39254a(20) =70755a(21) =127469a(22) =229725a(23) =413908a(24) =745889a(25) =1343980a(26) =2421850a(27) =4363921a(28) =7863641a(29) =14169633