Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2.

A209066

Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =5a(4) =8a(5) =19a(6) =39a(7) =95a(8) =223a(9) =554a(10) =1373a(11) =3493a(12) =8906a(13) =23016a(14) =59805a(15) =156588a(16) =412082a(17) =1090443a(18) =2897828a(19) =7733433a(20) =20712345a(21) =55661171a(22) =150031505a(23) =405533996a(24) =1098949141a(25) =2985066757a(26) =8125987470a(27) =22165517960a(28) =60575472281a(29) =165835969094

External references