Number of permutations of [2n] with n parity changes.

A363180

Number of permutations of [2n] with n parity changes.

Terms

    a(0) =1a(1) =2a(2) =8a(3) =288a(4) =10368a(5) =1036800a(6) =103680000a(7) =20321280000

External references