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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 24 |
| 5 | 1344 |
| 6 | 1128960 |
| 7 | 12198297600 |
| 8 | 2697818265354240 |
| 9 | 15224734061278915461120 |
| 10 | 2750892211809148994633229926400 |
| 11 | 19464657391668924966616671344752852992000 |
[1,1,1,2,24,1344,1128960,12198297600, 2697818265354240,15224734061278915461120, 2750892211809148994633229926400, 19464657391668924966616671344752852992000] |