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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 40 |
| 4 | 320 |
| 5 | 3840 |
| 6 | 72960 |
| 7 | 2188800 |
| 8 | 105062400 |
| 9 | 8089804800 |
| 10 | 1003135795200 |
| 11 | 200627159040000 |
| 12 | 64802572369920000 |
| 13 | 33826942777098240000 |
| 14 | 28549939703870914560000 |
| 15 | 38970667695783798374400000 |
| 16 | 86047234272290626810675200000 |
| 17 | 307360720820622118967731814400000 |
[1,2,8,40,320,3840,72960,2188800,105062400, 8089804800,1003135795200,200627159040000, 64802572369920000,33826942777098240000, 28549939703870914560000, 38970667695783798374400000, 86047234272290626810675200000, 307360720820622118967731814400000] |