Number of n-bead bracelets (turnover necklaces) with 12 red beads.

Terms

a(0) =1a(1) =1a(2) =7a(3) =19a(4) =72a(5) =196a(6) =561a(7) =1368a(8) =3260a(9) =7105a(10) =14938a(11) =29624a(12) =56822a(13) =104468a(14) =186616a(15) =322786a(16) =544802a(17) =896259a(18) =1444147a(19) =2278640a(20) =3532144a(21) =5380034a(22) =8070400a(23) =11926928a(24) =17393969a(25) =25042836a(26) =35638596a(27) =50152013a(28) =69855536