a(n) is the number of representative three-color bracelets (necklaces with turn over allowed) with n beads for n >= 3.

A214307

a(n) is the number of representative three-color bracelets (necklaces with turn over allowed) with n beads for n >= 3.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =20a(4) =40a(5) =106a(6) =304a(7) =731a(8) =1936a(9) =5769a(10) =14343a(11) =39583a(12) =117957a(13) =305576a(14) =855474a(15) =2565922a(16) =6793516a(17) =19242857a(18) =57827068a(19) =155681341a(20) =444461623a(21) =1337436721a(22) =3645877447a(23) =10471728930a(24) =31534868169a(25) =86818242806a(26) =250543852080a(27) =754851821246

External references