Number of self-dual 2-colored necklaces with 2n beads.

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =4a(5) =5a(6) =9a(7) =12a(8) =23a(9) =34a(10) =63a(11) =102a(12) =190a(13) =325a(14) =612a(15) =1088a(16) =2056a(17) =3771a(18) =7155a(19) =13364a(20) =25482a(21) =48175a(22) =92205a(23) =175792a(24) =337594a(25) =647326a(26) =1246863a(27) =2400842a(28) =4636390a(29) =8956060