Number of n-bead necklaces labeled with numbers -2..2 not allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.
A209109
Number of n-bead necklaces labeled with numbers -2..2 not allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.
Terms
- a(0) =1a(1) =3a(2) =5a(3) =22a(4) =63a(5) =238a(6) =865a(7) =3417a(8) =13607a(9) =55669a(10) =230581a(11) =968550a(12) =4108547a(13) =17589348a(14) =75872175a(15) =329480644a(16) =1439151627a(17) =6318822750a(18) =27872030921a(19) =123452835089
External references
- oeis: A209109