The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | -8 |
| 5 | -84 |
| 6 | -504 |
| 7 | -2304 |
| 8 | -6656 |
| 9 | 15760 |
| 10 | 484000 |
| 11 | 5348320 |
| 12 | 44393856 |
| 13 | 288642368 |
| 14 | 1137006976 |
| 15 | -5372233216 |
| 16 | -195241910272 |
| 17 | -2961479980800 |
| 18 | -34259767672320 |
| 19 | -320473550808576 |
| 20 | -2158264400250880 |
| 21 | -1727938748171264 |
| 22 | 278774033845987328 |
[0,1,2,2,-8,-84,-504,-2304,-6656,15760,484000, 5348320,44393856,288642368,1137006976,-5372233216, -195241910272,-2961479980800,-34259767672320, -320473550808576,-2158264400250880, -1727938748171264,278774033845987328] |