Permutations with large domain and large k

[ctrimble]

The following permutation is giving strange results:

permutations( 20,
  ONE, ONE, ONE, ONE, ONE,
  ONE, ONE, ONE, ONE, ONE,
  ONE, TWO, TWO, TWO, TWO,
  TWO, TWO, TWO, THREE, THREE ) }

This package needs a very clear table of the domains and k values that will work and those that will not, due to the imitations of the types being used.