Int returns a non-negative pseudo-random int.

Int63n returns, as an int64, a non-negative pseudo-random number in [0,n).

Intn returns, as an int, a non-negative pseudo-random number in [0,n).

Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).

Seed uses the provided seed value to initialize the default Source to a deterministic state.