The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | -2 |
| 4 | 15 |
| 5 | -36 |
| 6 | 104 |
| 7 | -312 |
| 8 | 1050 |
| 9 | -3312 |
| 10 | 10734 |
| 11 | -34518 |
| 12 | 113210 |
| 13 | -370236 |
| 14 | 1220922 |
| 15 | -4028696 |
| 16 | 13364424 |
| 17 | -44409312 |
[1,0,0,-2,15,-36,104,-312,1050,-3312,10734,-34518, 113210,-370236,1220922,-4028696,13364424, -44409312] |