Number of 5-level rooted trees with n leaves.

Terms

a(0) =1a(1) =1a(2) =5a(3) =15a(4) =55a(5) =170a(6) =571a(7) =1789a(8) =5727a(9) =17836a(10) =55627a(11) =171169a(12) =524879a(13) =1595896a(14) =4829894a(15) =14527981a(16) =43497312a(17) =129588391a(18) =384430264a(19) =1135607519a(20) =3341662498a(21) =9796626673a(22) =28620419254a(23) =83334382425a(24) =241879403752a(25) =699937499318