from typing import List


def prime_factors(n: int) -> List[int]:
  """Return an ascending list of the (greather-than-one) prime factors of n.

  >>> prime_factors(1)
  []

  >>> prime_factors(2)
  [2]

  >>> prime_factors(4)
  [2, 2]

  >>> prime_factors(60)
  [2, 2, 3, 5]
  """
  factors = []
  d = 2
  while d * d <= n:
    while (n % d) == 0:
      factors.append(d)
      n //= d
    d += 1
  if n > 1:
    factors.append(n)
  return factors