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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 23 |
| 4 | 404 |
| 5 | 9524 |
| 6 | 357264 |
| 7 | 16987536 |
| 8 | 1061800704 |
| 9 | 87631559424 |
| 10 | 8894837836800 |
| 11 | 1063107188812800 |
| 12 | 151494084266803200 |
| 13 | 25373057708287180800 |
| 14 | 5011895098867920076800 |
| 15 | 1135276451701834014720000 |
| 16 | 292340783888393707192320000 |
| 17 | 84048723407048386326036480000 |
[1,3,23,404,9524,357264,16987536,1061800704, 87631559424,8894837836800,1063107188812800, 151494084266803200,25373057708287180800, 5011895098867920076800,1135276451701834014720000, 292340783888393707192320000, 84048723407048386326036480000] |