Number of rooted compound windmills (mobiles) of n nodes.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =20a(6) =51a(7) =128a(8) =345a(9) =940a(10) =2632a(11) =7450a(12) =21434a(13) =62174a(14) =182146a(15) =537369a(16) =1596133a(17) =4767379a(18) =14312919a(19) =43162856a(20) =130695821a(21) =397184252a(22) =1211057426a(23) =3703794849a(24) =11358759346a(25) =34923477315a(26) =107627138308a(27) =332404636811