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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 12 |
| 6 | 5 |
| 7 | 72 |
| 8 | 315 |
| 9 | 2240 |
| 10 | 567 |
| 11 | 1814400 |
| 12 | 77 |
| 13 | 239500800 |
| 14 | 868725 |
| 15 | 7175168 |
| 16 | 49116375 |
| 17 | 2092278988800 |
| 18 | 14889875 |
| 19 | 3201186852864000 |
| 20 | 14849255421 |
| 21 | 3783802880000 |
| 22 | 3543572316375 |
| 23 | 562000363888803840000 |
| 24 | 2505147019375 |
| 25 | 496358721386591551488 |
[1,1,1,3,12,5,72,315,2240,567,1814400,77, 239500800,868725,7175168,49116375,2092278988800, 14889875,3201186852864000,14849255421, 3783802880000,3543572316375,562000363888803840000, 2505147019375,496358721386591551488] |