The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 30 |
| 8 | 0 |
| 9 | 840 |
| 10 | 0 |
| 11 | 0 |
| 12 | 0 |
| 13 | 1197504000 |
| 14 | 0 |
| 15 | 60281712691200 |
| 16 | 0 |
| 17 | 0 |
| 18 | 0 |
| 19 | 1348410350618155344199680000 |
[1,0,1,0,0,0,30,0,840,0,0,0,1197504000,0, 60281712691200,0,0,0,1348410350618155344199680000] |