Number of 7-leaf rooted trees with n levels.

Terms

a(0) =0a(1) =1a(2) =15a(3) =111a(4) =518a(5) =1789a(6) =5026a(7) =12166a(8) =26328a(9) =52221a(10) =96613a(11) =168861a(12) =281502a(13) =450905a(14) =697984a(15) =1048972a(16) =1536256a(17) =2199273a(18) =3085467a(19) =4251307a(20) =5763366a(21) =7699461a(22) =10149854a(23) =13218514a(24) =17024440a(25) =21703045a(26) =27407601a(27) =34310745a(28) =42606046a(29) =52509633