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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 144 |
| 7 | 28 |
| 8 | 1408 |
| 9 | 2025 |
| 10 | 86400 |
| 11 | 1782 |
| 12 | 1092096 |
| 13 | 4186 |
| 14 | 31360 |
| 15 | 241920000 |
| 16 | 23953408 |
| 17 | 140692 |
| 18 | 114108912 |
| 19 | 1092690 |
[1,2,6,24,120,144,28,1408,2025,86400,1782,1092096, 4186,31360,241920000,23953408,140692,114108912, 1092690] |