Number of asymmetric mobiles (circular rooted trees) with n nodes and 4 leaves.

Terms

a(0) =1a(1) =5a(2) =19a(3) =53a(4) =130a(5) =280a(6) =556a(7) =1024a(8) =1788a(9) =2971a(10) =4752a(11) =7338a(12) =11013a(13) =16099a(14) =23020a(15) =32249a(16) =44390a(17) =60109a(18) =80234a(19) =105670a(20) =137520a(21) =176979a(22) =225479a(23) =284562a(24) =356049a(25) =441890a(26) =544360a(27) =665883a(28) =809258a(29) =977455