Number of n-bead necklaces labeled with numbers -2..2 not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2.
A209067
Number of n-bead necklaces labeled with numbers -2..2 not allowing reversal, with sum zero and avoiding the pattern z z+1 z+2.
Terms
- a(0) =1a(1) =3a(2) =6a(3) =22a(4) =70a(5) =265a(6) =1007a(7) =4055a(8) =16593a(9) =69429a(10) =294509a(11) =1265692a(12) =5494398a(13) =24065829a(14) =106207739a(15) =471840078a(16) =2108406146a(17) =9470071142a(18) =42731427358a(19) =193612759011a(20) =880517540867
External references
- oeis: A209067