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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 90 |
| 7 | 3150 |
| 8 | 131040 |
| 9 | 6667920 |
| 10 | 416593800 |
| 11 | 31506454980 |
| 12 | 2841125225400 |
| 13 | 301392906637680 |
| 14 | 37173926260360890 |
| 15 | 5276692469017119150 |
| 16 | 854273993613848327520 |
| 17 | 156491796247034356836000 |
[0,0,0,0,0,0,90,3150,131040,6667920,416593800, 31506454980,2841125225400,301392906637680, 37173926260360890,5276692469017119150, 854273993613848327520,156491796247034356836000] |