The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | -3 |
| 5 | 10 |
| 6 | -100 |
| 7 | 525 |
| 8 | -5355 |
| 9 | 37980 |
| 10 | -440550 |
| 11 | 3927275 |
| 12 | -52278875 |
| 13 | 560837550 |
| 14 | -8500662300 |
| 15 | 106552684875 |
| 16 | -1819369836375 |
| 17 | 26079977287000 |
| 18 | -496530064488250 |
| 19 | 8007335798362875 |
| 20 | -168440275093179375 |
[1,0,0,0,-3,10,-100,525,-5355,37980,-440550, 3927275,-52278875,560837550,-8500662300, 106552684875,-1819369836375,26079977287000, -496530064488250,8007335798362875, -168440275093179375] |