This equation will calculate the odds of filling in a tournament bracket and having all of the teams placed (chosen) correctly to match the final outcome of the event.

This equation is a permutation,  it is based on choosing 2 teams, from a field of known teams, to compete in each of N number of events, such as games in a tournament.

Notes

The NCAA March Madness basketball tournament is a good example of when you could use this equation.   In the March Madness tournament,  68 teams compete for a National Championship game.  This tournament requires 63 coices of 'which team will be in this game",   so the permutations is `2^63`.   This means the odds of picking a Perfect Tournament bracket is 1 in 9,223,372,036,854,775,808.

Likewise,  if you want to use this equation for a little league tournament or for the number of ways your family could be seated / arranged around the table for a big meal,  these permutations can also be evaluated with this equation.

For example:  if 12 people are coming to your house for dinner,  and you want to seat them as couples.  We suppose there are 12 chairs,  you will have to pick 6 sets of two to place around the table.  This is the same as picking the teams for a tournament,  you must pick two people for each of 6 (paired) places.   That would be `2^6` or 64 possible arrangements to consider.

Likewise,  if your are only considering choosing teams for the Sweet SIxteen,  That will be twelve games which will be played,  so you have choices to make equalling   `2^12` or  4096 possible choices.