Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero with no three beads in a row equal.

A208938

Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero with no three beads in a row equal.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =5a(4) =8a(5) =20a(6) =38a(7) =88a(8) =196a(9) =464a(10) =1088a(11) =2628a(12) =6344a(13) =15554a(14) =38318a(15) =95170a(16) =237536a(17) =596286a(18) =1503098a(19) =3805452a(20) =9668776a(21) =24650428a(22) =63035390a(23) =161648194a(24) =415589336a(25) =1071003162a(26) =2766083600a(27) =7158525512a(28) =18561001524a(29) =48210881198

External references