The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 630 |
| 8 | 28560 |
| 9 | 1330560 |
| 10 | 74314800 |
| 11 | 5057098200 |
| 12 | 413836259760 |
| 13 | 40145915529720 |
| 14 | 4558576721418720 |
| 15 | 599227672837944150 |
| 16 | 90306248160926397600 |
| 17 | 15470047011889029399840 |
| 18 | 2989635481745274974582880 |
[0,0,0,0,0,0,0,630,28560,1330560,74314800, 5057098200,413836259760,40145915529720, 4558576721418720,599227672837944150, 90306248160926397600,15470047011889029399840, 2989635481745274974582880] |