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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 210 |
| 3 | 4544 |
| 4 | 114918 |
| 5 | 3294600 |
| 6 | 104940100 |
| 7 | 3660744000 |
| 8 | 138361492380 |
| 9 | 5618752289360 |
| 10 | 243511994967000 |
| 11 | 11200919966016000 |
| 12 | 544286360757205000 |
| 13 | 27831091180723010400 |
| 14 | 1492408800133053250800 |
| 15 | 83678952234578405408000 |
[1,12,210,4544,114918,3294600,104940100, 3660744000,138361492380,5618752289360, 243511994967000,11200919966016000, 544286360757205000,27831091180723010400, 1492408800133053250800,83678952234578405408000] |