This short article was prompted by the formula for Prob(N) in Michael Keith's "What are the odds that X is an anagram of Y?" in Word Ways, August 2000. It seemed to me that multiplying the values of that function by the square of the number of words of a given length might be expected to give an estimate of the number of words of a given length that are permutations of another word.
"How Many Anagrams Are There?,"
Word Ways: Vol. 33
, Article 8.
Available at: http://digitalcommons.butler.edu/wordways/vol33/iss4/8