Number of 4-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.
A209116
Number of 4-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) =5a(1) =22a(2) =55a(3) =120a(4) =221a(5) =362a(6) =559a(7) =816a(8) =1137a(9) =1538a(10) =2023a(11) =2596a(12) =3273a(13) =4058a(14) =4955a(15) =5980a(16) =7137a(17) =8430a(18) =9875a(19) =11476a(20) =13237a(21) =15174a(22) =17291a(23) =19592a(24) =22093a(25) =24798a(26) =27711a(27) =30848a(28) =34213a(29) =37810
External references
- oeis: A209116