In how many ways can 8 persons be seated at a round table so that all shall not have the same neighbours in any two arrangements?

In how many ways can 6 persons be seated at a round table?

In how many ways can 5 persons be seated at a round table?

In how many ways can 6 persons be seated at a round table?

In how many ways can 6 persons can be seated at a round table so that all shall not have the same neighbours in any two arrangements?

In how many ways can 8 boys be seated at a round table?

In how many ways can 7 persons sit around a table so that all shall not have the same neighbours in any two arrangements?

In how many ways can 7 persons sit around a table so that all shall not have the same neighbours in any two arrangements.