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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 12 |
| 4 | 20 |
| 5 | 60 |
| 6 | 360 |
| 7 | 630 |
| 8 | 2520 |
| 9 | 4480 |
| 10 | 20160 |
| 11 | 36288 |
| 12 | 181440 |
| 13 | 1814400 |
| 14 | 3326400 |
| 15 | 19958400 |
| 16 | 239500800 |
| 17 | 444787200 |
| 18 | 3113510400 |
| 19 | 5811886080 |
| 20 | 43589145600 |
| 21 | 81729648000 |
| 22 | 653837184000 |
| 23 | 1302884352000 |
| 24 | 10461394944000 |
| 25 | 19760412672000 |
| 26 | 177843714048000 |
| 27 | 3201186852864000 |
[1,3,12,20,60,360,630,2520,4480,20160,36288, 181440,1814400,3326400,19958400,239500800, 444787200,3113510400,5811886080,43589145600, 81729648000,653837184000,1302884352000, 10461394944000,19760412672000,177843714048000, 3201186852864000] |