G.f. A(x) satisfies A(x) = 1 + x/(1+x^3)^2 * A(x)^2.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =12a(5) =34a(6) =102a(7) =320a(8) =1030a(9) =3383a(10) =11290a(11) =38176a(12) =130512a(13) =450350a(14) =1566458a(15) =5486541a(16) =19333804a(17) =68496366a(18) =243833190a(19) =871719749a(20) =3128496100a(21) =11267070349a(22) =40706748704a(23) =147496902650a(24) =535866079848