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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 80 |
| 3 | 720 |
| 4 | 6552 |
| 5 | 58960 |
| 6 | 531360 |
| 7 | 4782160 |
| 8 | 43045920 |
| 9 | 387413208 |
| 10 | 3486777120 |
| 11 | 31380993360 |
| 12 | 282429470960 |
| 13 | 2541865231440 |
| 14 | 22876791858720 |
| 15 | 205891126722080 |
| 16 | 1853020183479912 |
| 17 | 16677181651254480 |
| 18 | 150094635248646000 |
| 19 | 1350851717237225040 |
| 20 | 12157665458621220720 |
[1,8,80,720,6552,58960,531360,4782160,43045920, 387413208,3486777120,31380993360,282429470960, 2541865231440,22876791858720,205891126722080, 1853020183479912,16677181651254480, 150094635248646000,1350851717237225040, 12157665458621220720] |