G.f. satisfies A(x) = 1 + x/(1 - x^4)^2 * A(x/(1 - x^4)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =6a(7) =10a(8) =15a(9) =24a(10) =51a(11) =109a(12) =214a(13) =389a(14) =747a(15) =1595a(16) =3497a(17) =7379a(18) =15065a(19) =31750a(20) =70504a(21) =159352a(22) =353748a(23) =777240a(24) =1742696a(25) =4022595a(26) =9379659a(27) =21717264a(28) =50239529a(29) =117913537