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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 360 |
| 4 | 20160 |
| 5 | 1814400 |
| 6 | 239500800 |
| 7 | 43589145600 |
| 8 | 10461394944000 |
| 9 | 3201186852864000 |
| 10 | 1216451004088320000 |
| 11 | 562000363888803840000 |
| 12 | 310224200866619719680000 |
| 13 | 201645730563302817792000000 |
| 14 | 152444172305856930250752000000 |
| 15 | 132626429906095529318154240000000 |
[1,12,360,20160,1814400,239500800,43589145600, 10461394944000,3201186852864000, 1216451004088320000,562000363888803840000, 310224200866619719680000, 201645730563302817792000000, 152444172305856930250752000000, 132626429906095529318154240000000] |