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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 12 |
| 3 | 360 |
| 4 | 20160 |
| 5 | 1814400 |
| 6 | 34214400 |
| 7 | 3962649600 |
| 8 | 10461394944000 |
| 9 | 457312407552000 |
| 10 | 1216451004088320000 |
| 11 | 562000363888803840000 |
| 12 | 309914286580039680000 |
| 13 | 10612933187542253568000000 |
| 14 | 152444172305856930250752000000 |
| 15 | 18946632843727932759736320000000 |
[1,1,12,360,20160,1814400,34214400,3962649600, 10461394944000,457312407552000, 1216451004088320000,562000363888803840000, 309914286580039680000,10612933187542253568000000, 152444172305856930250752000000, 18946632843727932759736320000000] |