Number of 9-leaf rooted trees with n levels.

Terms

a(0) =0a(1) =1a(2) =30a(3) =424a(4) =3357a(5) =17836a(6) =71769a(7) =236093a(8) =667335a(9) =1676364a(10) =3832477a(11) =8113347a(12) =16112746a(13) =30319341a(14) =54481246a(15) =94072398a(16) =156878210a(17) =253719339a(18) =399333792a(19) =613438978a(20) =921996699a(21) =1358705458a(22) =1966745847a(23) =2800806163a(24) =3929416785a(25) =5437623230a(26) =7430029191a(27) =10034242245