Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and first differences in -1..1.
A208986
Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and first differences in -1..1.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =5a(6) =9a(7) =18a(8) =35a(9) =73a(10) =151a(11) =324a(12) =691a(13) =1503a(14) =3277a(15) =7212a(16) =15927a(17) =35407a(18) =78967a(19) =176942a(20) =397717a(21) =897079a(22) =2029071a(23) =4602438a(24) =10464647a(25) =23849545a(26) =54468627a(27) =124646180a(28) =285762575a(29) =656268311
External references
- oeis: A208986