Number of arrangements of 2n couples into n cars such that each car contains 2 men and 2 women but no couple (cars are labeled).

A137801

Number of arrangements of 2n couples into n cars such that each car contains 2 men and 2 women but no couple (cars are labeled).

Terms

    a(0) =0a(1) =6a(2) =900a(3) =748440a(4) =1559930400

External references