G.f. satisfies: A(x) = Product_{n>=1} (1 + x^n) * (1 + x^(2n)*A(x)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =14a(6) =27a(7) =53a(8) =104a(9) =208a(10) =415a(11) =836a(12) =1690a(13) =3434a(14) =7004a(15) =14342a(16) =29460a(17) =60707a(18) =125443a(19) =259883a(20) =539689a(21) =1123226a(22) =2342493a(23) =4894590a(24) =10245321a(25) =21481047a(26) =45108768a(27) =94863801a(28) =199772929a(29) =421245065