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

Terms

a(0) =1a(1) =1a(2) =3a(3) =8a(4) =20a(5) =51a(6) =130a(7) =331a(8) =843a(9) =2147a(10) =5468a(11) =13926a(12) =35467a(13) =90328a(14) =230049a(15) =585893a(16) =1492163a(17) =3800268a(18) =9678592a(19) =24649615a(20) =62778090a(21) =159884387a(22) =407196479a(23) =1037055435a(24) =2641191736a(25) =6726635386a(26) =17131517943a(27) =43630863008a(28) =111119879345a(29) =283002139641