Number of n-bead necklaces with 3 colors.

Terms

a(0) =1a(1) =3a(2) =6a(3) =11a(4) =24a(5) =51a(6) =130a(7) =315a(8) =834a(9) =2195a(10) =5934a(11) =16107a(12) =44368a(13) =122643a(14) =341802a(15) =956635a(16) =2690844a(17) =7596483a(18) =21524542a(19) =61171659a(20) =174342216a(21) =498112275a(22) =1426419858a(23) =4093181691a(24) =11767920118a(25) =33891544419a(26) =97764131646a(27) =282429537947a(28) =817028472960