Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero.
A208819
Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero.
Terms
- a(0) =1a(1) =3a(2) =5a(3) =16a(4) =45a(5) =167a(6) =609a(7) =2471a(8) =10143a(9) =43223a(10) =186533a(11) =818836a(12) =3629835a(13) =16250859a(14) =73300289a(15) =332895316a(16) =1520604469a(17) =6981991345a(18) =32205476541
External references
- oeis: A208819