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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 12 |
| 4 | 114 |
| 5 | 940 |
| 6 | 7568 |
| 7 | 61728 |
| 8 | 512996 |
| 9 | 4334884 |
| 10 | 37164700 |
| 11 | 322624804 |
| 12 | 2830973320 |
| 13 | 25074130996 |
| 14 | 223900666504 |
| 15 | 2013718244072 |
[1,12,114,940,7568,61728,512996,4334884,37164700, 322624804,2830973320,25074130996,223900666504, 2013718244072] |