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| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 72 |
| 3 | 504 |
| 4 | 3024 |
| 5 | 15120 |
| 6 | 60480 |
| 7 | 181440 |
| 8 | 362880 |
| 9 | 362880 |
| 10 | 32659200 |
| 11 | 2906668800 |
| 12 | 255786854400 |
| 13 | 22253456332800 |
| 14 | 1913797244620800 |
| 15 | 162672765792768000 |
| 16 | 13664512326592512000 |
| 17 | 1134154523107178496000 |
| 18 | 93000670894788636672000 |
| 19 | 7533054342477879570432000 |
[9,72,504,3024,15120,60480,181440,362880,362880, 32659200,2906668800,255786854400,22253456332800, 1913797244620800,162672765792768000, 13664512326592512000,1134154523107178496000, 93000670894788636672000,7533054342477879570432000] |