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| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 8 |
| 3 | 4 |
| 4 | 76 |
| 5 | 880 |
| 6 | 280 |
| 7 | 4960 |
| 8 | 59680 |
| 9 | 637120 |
| 10 | 6371200 |
| 11 | 60083200 |
| 12 | 520998400 |
| 13 | 3772979200 |
| 14 | 12821708800 |
| 15 | 8692325632000 |
| 16 | 79077210112000 |
| 17 | 644312571904000 |
| 18 | 3597626294272000 |
| 19 | 878354899591168000 |
| 20 | 7567097991823360000 |
| 21 | 48909057828290560000 |
| 22 | 8875999272222392320000 |
[9,8,4,76,880,280,4960,59680,637120,6371200, 60083200,520998400,3772979200,12821708800, 8692325632000,79077210112000,644312571904000, 3597626294272000,878354899591168000, 7567097991823360000,48909057828290560000, 8875999272222392320000] |