Number of n-bead necklaces labeled with numbers -4..4 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.
A209481
Number of n-bead necklaces labeled with numbers -4..4 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) =5a(2) =12a(3) =72a(4) =390a(5) =2606a(6) =17771a(7) =128598a(8) =950292a(9) =7180767a(10) =55056590a(11) =427567892a(12) =3354737555a(13) =26555548849
External references
- oeis: A209481