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| n | a(n) |
|---|---|
| 7 | 1 |
| 8 | 28 |
| 9 | 630 |
| 10 | 14070 |
| 11 | 331485 |
| 12 | 8411634 |
| 13 | 231354123 |
| 14 | 6899167275 |
| 15 | 222569372025 |
| 16 | 7741879425280 |
| 17 | 289297137120992 |
| 18 | 11570476164077376 |
| 19 | 493535471267193810 |
| 20 | 22376155441920000000 |
| 21 | 1074961750207964923710 |
| 22 | 54561107576767408522752 |
| 23 | 2918071167402563863036269 |
[1,28,630,14070,331485,8411634,231354123, 6899167275,222569372025,7741879425280, 289297137120992,11570476164077376, 493535471267193810,22376155441920000000, 1074961750207964923710,54561107576767408522752, 2918071167402563863036269] |