Number of free treelike midpoint-free polycubes of size n, identifying rotations and reflections.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =4a(5) =12a(6) =23a(7) =47a(8) =91a(9) =202a(10) =428a(11) =911a(12) =1862a(13) =3638a(14) =6637a(15) =11780a(16) =20764a(17) =36904a(18) =64855a(19) =111552a(20) =186147a(21) =302526a(22) =479076a(23) =739080a(24) =1106514a(25) =1610045a(26) =2278632a(27) =3146000a(28) =4254002a(29) =5682571