Number of n-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.
A209107
Number of n-bead necklaces labeled with numbers -n..n 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) =11a(3) =120a(4) =1683a(5) =32802a(6) =802125a(7) =23766209a(8) =827695021a(9) =33165786247
External references
- oeis: A209107