G.f. satisfies: A(x - A(x) + A(x)^2) = -x^4.

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =16a(5) =48a(6) =152a(7) =501a(8) =1690a(9) =5822a(10) =20388a(11) =72360a(12) =259688a(13) =940792a(14) =3435904a(15) =12636554a(16) =46760376a(17) =173971252a(18) =650380288a(19) =2441905192a(20) =9203979808a(21) =34813551616a(22) =132101846848a(23) =502732914346