Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and three times sum of squares <= n*(1)*(1+1).
A208807
Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and three times sum of squares <= n*(1)*(1+1).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =4a(4) =5a(5) =22a(6) =37a(7) =62a(8) =281a(9) =558a(10) =1031a(11) =4700a(12) =9913a(13) =19766a(14) =87719a(15) =193172a(16) =403805a(17) =1757552a(18) =3983935a(19) =8629150a(20) =36900723a(21) =85538100a(22) =190374581a(23) =801821488a(24) =1891960745a(25) =4303219652a(26) =17883751583a(27) =42817714086a(28) =99138620363a(29) =407163066510
External references
- oeis: A208807