Number of n-bead necklaces labeled with numbers 1..n allowing reversal, with no adjacent beads differing by more than 1.

A208715

Number of n-bead necklaces labeled with numbers 1..n allowing reversal, with no adjacent beads differing by more than 1.

Terms

    a(0) =1a(1) =3a(2) =7a(3) =18a(4) =38a(5) =100a(6) =224a(7) =600a(8) =1498a(9) =4124a(10) =11054a(11) =31347a(12) =87887a(13) =253251a(14) =727867a(15) =2117551a(16) =6159994a(17) =18022052a(18) =52757222a(19) =154874172a(20) =454989753a(21) =1338737083a(22) =3941860229a(23) =11618101775a(24) =34264747423a(25) =101127761931a(26) =298632667837a(27) =882370316215

External references