Number of permutations of the multiset {1,1,2,2,...,n,n} with no two consecutive terms equal.

A114938

Number of permutations of the multiset {1,1,2,2,...,n,n} with no two consecutive terms equal.

Terms

    a(0) =1a(1) =0a(2) =2a(3) =30a(4) =864a(5) =39480a(6) =2631600a(7) =241133760a(8) =29083420800

External references