Number of n-bead bracelets (turnover necklaces) of two colors with 6 red beads and n-6 black beads.

Terms

a(0) =1a(1) =1a(2) =4a(3) =7a(4) =16a(5) =26a(6) =50a(7) =76a(8) =126a(9) =185a(10) =280a(11) =392a(12) =561a(13) =756a(14) =1032a(15) =1353a(16) =1782a(17) =2277a(18) =2920a(19) =3652a(20) =4576a(21) =5626a(22) =6916a(23) =8372a(24) =10133a(25) =12103a(26) =14448a(27) =17063a(28) =20128a(29) =23528