Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.
A209479
Number of n-bead necklaces labeled with numbers -2..2 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) =3a(2) =4a(3) =15a(4) =38a(5) =136a(6) =458a(7) =1781a(8) =6912a(9) =28141a(10) =115761a(11) =485607a(12) =2056341a(13) =8800541a(14) =37945282a(15) =164766522a(16) =719617100a(17) =3159529303a(18) =13936202144
External references
- oeis: A209479