Number of bracelets (turnover necklaces) of n beads of 2 colors, 5 of them black.

Terms

a(0) =1a(1) =1a(2) =3a(3) =5a(4) =10a(5) =16a(6) =26a(7) =38a(8) =57a(9) =79a(10) =111a(11) =147a(12) =196a(13) =252a(14) =324a(15) =406a(16) =507a(17) =621a(18) =759a(19) =913a(20) =1096a(21) =1298a(22) =1534a(23) =1794a(24) =2093a(25) =2421a(26) =2793a(27) =3199a(28) =3656a(29) =4152