The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | -1 |
| 4 | -10 |
| 5 | -6 |
| 6 | 294 |
| 7 | 1350 |
| 8 | -14624 |
| 9 | -197568 |
| 10 | 703800 |
| 11 | 34790040 |
| 12 | 100585968 |
| 13 | -7259053296 |
| 14 | -85604489712 |
| 15 | 1588693382640 |
| 16 | 46549054391040 |
| 17 | -216669088277760 |
| 18 | -24865626969568512 |
| 19 | -159153249738896640 |
| 20 | 13379663931502199040 |
[1,1,1,-1,-10,-6,294,1350,-14624,-197568,703800, 34790040,100585968,-7259053296,-85604489712, 1588693382640,46549054391040,-216669088277760, -24865626969568512,-159153249738896640, 13379663931502199040] |