Lah numbers: a(n) = n!*binomial(n-1,2)/6.

A001754

Lah numbers: a(n) = n!*binomial(n-1,2)/6.

Terms

    a(0) =0a(1) =0a(2) =1a(3) =12a(4) =120a(5) =1200a(6) =12600a(7) =141120a(8) =1693440a(9) =21772800a(10) =299376000a(11) =4390848000a(12) =68497228800

External references