The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 24 |
| 4 | 1152 |
| 5 | 1399680 |
| 6 | 290237644800 |
| 7 | 520105859481600000000 |
| 8 | 3435834286784202670080000000000000000 |
| 9 | 3045775242579858715944293498880000000000000000000000000000000000 |
[1,2,24,1152,1399680,290237644800, 520105859481600000000, 3435834286784202670080000000000000000, 30457752425798587159442934988800000000000000000000\ 00000000000000] |