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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | -4 |
| 5 | -6 |
| 6 | 30 |
| 7 | -240 |
| 8 | 1260 |
| 9 | 35700 |
| 10 | 1256640 |
| 11 | -199020360 |
| 12 | -202839655480 |
| 13 | 1124753048683264 |
| 14 | -181696576073176468304 |
| 15 | 1026657060420588391021488976 |
| 16 | 919637161132261232937508950440493056 |
| 17 | 839430326120023909391651548323223480699275649536 |
[-1,1,1,1,-4,-6,30,-240,1260,35700,1256640, -199020360,-202839655480,1124753048683264, -181696576073176468304, 1026657060420588391021488976, 919637161132261232937508950440493056, 839430326120023909391651548323223480699275649536] |