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How to find number of n-element permutations with exactly k inversions?? (n,k are given)

I know some solutions:
1.) Using Merge Sort ( the complexity is O(n log n) )
2.) Using DP ( this is the fastest algorithm for this problem that I have heard of )

Probably there exist a formula ?

tytus wrote:How to find number of n-element permutations with exactly k inversions?? (n,k are given)

http://academic.csuohio.edu/bmargolius/ ... invers.htm