In a 2v2 competition with 10 different players. How many different permutations of those 10 players are there?

My guess at the formula would be:

1/k^2(n!/(n-k)!)

Where n is the number of players and k is the type of tournament.

Which would give the number of combinations as:

315

But I dont think this solution is correct.

Can anyone help me out?

Thanks.