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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 3 |
| 4 | 8 |
| 5 | 150 |
| 6 | 84 |
| 7 | 5040 |
| 8 | 39808 |
| 9 | 72576 |
| 10 | 5598000 |
| 11 | 19617840 |
| 12 | 392747904 |
| 13 | 9837828000 |
| 14 | 23366133504 |
| 15 | 2120992080480 |
| 16 | 23679285857280 |
| 17 | 236064853301760 |
| 18 | 13280228754130944 |
| 19 | 79239777198727680 |
| 20 | 3793985724604769280 |
| 21 | 97004042539092541440 |
| 22 | 781106411330024693760 |
[1,0,2,3,8,150,84,5040,39808,72576,5598000, 19617840,392747904,9837828000,23366133504, 2120992080480,23679285857280,236064853301760, 13280228754130944,79239777198727680, 3793985724604769280,97004042539092541440, 781106411330024693760] |