Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero and first and second differences in -2..2.

A208964

Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero and first and second differences in -2..2.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =3a(4) =3a(5) =8a(6) =15a(7) =42a(8) =94a(9) =246a(10) =613a(11) =1645a(12) =4361a(13) =11980a(14) =33023a(15) =92484a(16) =259762a(17) =735310a(18) =2088403a(19) =5961138a(20) =17070131a(21) =49059542a(22) =141402328a(23) =408736264a(24) =1184435227a(25) =3440434897a(26) =10014880408a(27) =29211476668a(28) =85362417183a(29) =249882401380

External references