Number of n-bead necklaces labeled with numbers 1..4 allowing reversal, with no adjacent beads differing by more than 1.

A208717

Number of n-bead necklaces labeled with numbers 1..4 allowing reversal, with no adjacent beads differing by more than 1.

Terms

    a(0) =4a(1) =7a(2) =10a(3) =18a(4) =28a(5) =56a(6) =98a(7) =208a(8) =418a(9) =933a(10) =2044a(11) =4777a(12) =11072a(13) =26548a(14) =63672a(15) =155248a(16) =379348a(17) =935278a(18) =2311294a(19) =5741228a(20) =14292966a(21) =35699049a(22) =89339860a(23) =224097602a(24) =563074848a(25) =1417313897a(26) =3572747650a(27) =9019154944a(28) =22797181996a(29) =57693378135

External references