n*n!/round(n/2).

A256880

n*n!/round(n/2).

Terms

    a(0) =1a(1) =4a(2) =9a(3) =48a(4) =200a(5) =1440a(6) =8820a(7) =80640a(8) =653184a(9) =7257600a(10) =73180800a(11) =958003200a(12) =11564467200a(13) =174356582400

External references