G.f. A(x) satisfies A(x) = 1 + x^4 * (A(x) / (1 - x))^3.

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =1a(5) =3a(6) =6a(7) =10a(8) =18a(9) =39a(10) =91a(11) =204a(12) =435a(13) =919a(14) =1992a(15) =4434a(16) =9947a(17) =22215a(18) =49455a(19) =110480a(20) =248505a(21) =561930a(22) =1273610a(23) =2889666a(24) =6566736a(25) =14959083a(26) =34163511a(27) =78182700a(28) =179201199a(29) =411325125