How many necklace of 12 beads, each can be made from 18 beads of various colours?

Explanation

In the case of necklace, there is no distinction between the clockwise and anti-clockwise arrangement, the required number of circular permutations.
`=(.^(18)P_(12))/(2xx12)=(18!)/(6!xx24)=(18xx17xx16xx15xx14xx13!)/(6xx5xx4xx3xx2xx1xx24)=(119xx13!)/(2)`