This is my first post on math.stackexchange. I am wondering how many possible seedings there could be in a seeded NCAA March Madness tournament. As a user suggests here, the number of outcomes of an already seeded bracket is
$2^{32}\times 2^{16}\times 2^8\times 2^4\times 2^2\times 2^1$.
But does this include the number of ways to seed the bracket? It seems as though $2^{32}$ is counting the number of outcomes of the first round, which is already seeded. I have done a search and nobody has seemed to address the seeding (or explicitly said it.)
Is it just $\frac{64!}{2^{64}}$? The $64!$ comes from the number of ways to order the teams, and the $2^{64}$ comes from symmetry in the arrangements? That is a vs b is the same as b vs a.