Number of 5-bead necklaces of n colors not allowing reversal, with no adjacent beads having the same color.

A208536

Number of 5-bead necklaces of n colors not allowing reversal, with no adjacent beads having the same color.

Terms

    a(0) =0a(1) =0a(2) =6a(3) =48a(4) =204a(5) =624a(6) =1554a(7) =3360a(8) =6552a(9) =11808a(10) =19998a(11) =32208a(12) =49764a(13) =74256a(14) =107562a(15) =151872a(16) =209712a(17) =283968a(18) =377910a(19) =495216a(20) =639996a(21) =816816a(22) =1030722a(23) =1287264a(24) =1592520a(25) =1953120a(26) =2376270a(27) =2869776a(28) =3442068a(29) =4102224

External references