Number of n-bead necklaces labeled with numbers -3..3 allowing reversal, with sum zero and first differences in -3..3.

A209027

Number of n-bead necklaces labeled with numbers -3..3 allowing reversal, with sum zero and first differences in -3..3.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =12a(4) =34a(5) =144a(6) =576a(7) =2613a(8) =11841a(9) =55773a(10) =265095a(11) =1280476a(12) =6238246a(13) =30674021a(14) =151874427a(15) =756842052a(16) =3792315084a(17) =19096602857a(18) =96586072494a(19) =490453174481

External references