Number of orbits of size 2n in vertex graph of Lucas cube Lambda_n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =1a(9) =1a(10) =3a(11) =5a(12) =10a(13) =15a(14) =30a(15) =44a(16) =78a(17) =119a(18) =202a(19) =310a(20) =513a(21) =786a(22) =1277a(23) =1977a(24) =3168a(25) =4916a(26) =7831a(27) =12199a(28) =19332a(29) =30208