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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 280 |
| 3 | 23100 |
| 4 | 2522520 |
| 5 | 325909584 |
| 6 | 47117214144 |
| 7 | 7383099180600 |
| 8 | 1229149289511000 |
| 9 | 214527522662653200 |
| 10 | 38887279926227853120 |
| 11 | 7271332144993605081120 |
| 12 | 1395321310426879365566400 |
| 13 | 273697641660657106322640000 |
| 14 | 54708248601655917595233984000 |
[1,6,280,23100,2522520,325909584,47117214144, 7383099180600,1229149289511000,214527522662653200, 38887279926227853120,7271332144993605081120, 1395321310426879365566400, 273697641660657106322640000, 54708248601655917595233984000] |