G.f. A(x) satisfies A(x) = 1 / ((1 + x) * (1 - x * (1 + x) * A(x^2))).

Terms

a(0) =1a(1) =0a(2) =2a(3) =1a(4) =4a(5) =6a(6) =13a(7) =23a(8) =44a(9) =82a(10) =154a(11) =292a(12) =547a(13) =1036a(14) =1943a(15) =3672a(16) =6900a(17) =13022a(18) =24498a(19) =46194a(20) =86958a(21) =163892a(22) =308624a(23) =581532a(24) =1095275a(25) =2063534a(26) =3886876a(27) =7322523a(28) =13793363a(29) =25984580