Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero and first and second differences in -1..1.
A208963
Number of n-bead necklaces labeled with numbers -1..1 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) =2a(7) =4a(8) =4a(9) =7a(10) =7a(11) =14a(12) =16a(13) =32a(14) =46a(15) =90a(16) =140a(17) =258a(18) =416a(19) =746a(20) =1245a(21) =2228a(22) =3845a(23) =6929a(24) =12194a(25) =21990a(26) =39113a(27) =70544a(28) =126293a(29) =228168
External references
- oeis: A208963