Number of sets of nonempty words with a total of 2n letters over n-ary alphabet such that all n letters occur at least once in the set.

A319519

Number of sets of nonempty words with a total of 2n letters over n-ary alphabet such that all n letters occur at least once in the set.

Terms

    a(0) =1a(1) =1a(2) =38a(3) =2811a(4) =375698a(5) =78808600a(6) =23761098837

External references