G.f. A(x) satisfies A(x) = 1 - x/A(x)^3 * (1 - A(x) - A(x)^5).

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =15a(5) =43a(6) =168a(7) =626a(8) =2005a(9) =6245a(10) =22266a(11) =87365a(12) =328727a(13) =1154975a(14) =4086410a(15) =15464587a(16) =60368094a(17) =229327457a(18) =847539610a(19) =3174058754a(20) =12277874065a(21) =47912709420a(22) =184171945435a(23) =701491726600