Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and first and second differences in -1..1.
A209000
Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and first and second differences in -1..1.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =2a(6) =3a(7) =5a(8) =7a(9) =10a(10) =13a(11) =20a(12) =29a(13) =51a(14) =85a(15) =155a(16) =265a(17) =471a(18) =803a(19) =1408a(20) =2437a(21) =4309a(22) =7599a(23) =13590a(24) =24231a(25) =43506a(26) =77953a(27) =140219a(28) =252095a(29) =454761
External references
- oeis: A209000