Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly n local maxima.

A334779

Number of permutations of 2 indistinguishable copies of 1..n arranged in a circle with exactly n local maxima.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =88a(5) =1480a(6) =40272a(7) =1476944a(8) =71865728a(9) =4454840448a(10) =343059301120

External references