The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 1440 |
| 7 | 15120 |
| 8 | 161280 |
| 9 | 2177280 |
| 10 | 32659200 |
| 11 | 518918400 |
| 12 | 9101030400 |
| 13 | 174356582400 |
| 14 | 3574309939200 |
| 15 | 78460462080000 |
| 16 | 1841205510144000 |
| 17 | 45883678224384000 |
| 18 | 1210048630382592000 |
[1,0,0,6,24,120,1440,15120,161280,2177280, 32659200,518918400,9101030400,174356582400, 3574309939200,78460462080000,1841205510144000, 45883678224384000,1210048630382592000] |