The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 252 |
| 4 | 41580 |
| 5 | 29729700 |
| 6 | 89278289100 |
| 7 | 1104908105901600 |
| 8 | 55674109640169820800 |
| 9 | 11329124570678156834592000 |
| 10 | 9258047307912482983660236480000 |
| 11 | 30262334718212007877669234596364800000 |
[1,7,252,41580,29729700,89278289100, 1104908105901600,55674109640169820800, 11329124570678156834592000, 9258047307912482983660236480000, 30262334718212007877669234596364800000] |