G.f. A(x) satisfies: A(x)^4 = x * A( A(x)^3 + A(x)^4 ).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =7a(5) =22a(6) =61a(7) =172a(8) =528a(9) =1696a(10) =5461a(11) =17591a(12) =57356a(13) =189786a(14) =634137a(15) =2131628a(16) =7205426a(17) =24500143a(18) =83760349a(19) =287672215a(20) =991932713a(21) =3432816902a(22) =11920342010a(23) =41521046864a(24) =145032773711a(25) =507902711094