Number of n-bead necklace structures which are not self-equivalent under a nonzero rotation using exactly three different colored beads.

A328740

Number of n-bead necklace structures which are not self-equivalent under a nonzero rotation using exactly three different colored beads.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =5a(5) =13a(6) =43a(7) =116a(8) =335a(9) =920a(10) =2591a(11) =7173a(12) =20125a(13) =56260a(14) =158333a(15) =446098a(16) =1262225a(17) =3579227a(18) =10181479a(19) =29028405a(20) =82968695a(21) =237634700a(22) =682014587a(23) =1960951980a(24) =5647919640a(25) =16292680600a(26) =47069103545a(27) =136166476875a(28) =394418199725

External references