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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 90 |
| 3 | 1344 |
| 4 | 25200 |
| 5 | 570240 |
| 6 | 15135120 |
| 7 | 461260800 |
| 8 | 15878903040 |
| 9 | 609493248000 |
| 10 | 25812039052800 |
| 11 | 1195656969830400 |
| 12 | 60138698780160000 |
| 13 | 3264143527636992000 |
| 14 | 190165504623494400000 |
| 15 | 11836497605427855360000 |
| 16 | 783921372659482337280000 |
[1,8,90,1344,25200,570240,15135120,461260800, 15878903040,609493248000,25812039052800, 1195656969830400,60138698780160000, 3264143527636992000,190165504623494400000, 11836497605427855360000,783921372659482337280000] |