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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 12 |
| 5 | 30 |
| 6 | 30 |
| 7 | 210 |
| 8 | 560 |
| 9 | 560 |
| 10 | 4200 |
| 11 | 11550 |
| 12 | 11550 |
| 13 | 90090 |
| 14 | 252252 |
| 15 | 252252 |
| 16 | 2018016 |
| 17 | 5717712 |
| 18 | 5717712 |
| 19 | 46558512 |
| 20 | 133024320 |
| 21 | 133024320 |
| 22 | 1097450640 |
| 23 | 3155170590 |
| 24 | 3155170590 |
| 25 | 26293088250 |
| 26 | 75957810500 |
| 27 | 75957810500 |
| 28 | 638045608200 |
[1,2,2,12,30,30,210,560,560,4200,11550,11550, 90090,252252,252252,2018016,5717712,5717712, 46558512,133024320,133024320,1097450640, 3155170590,3155170590,26293088250,75957810500, 75957810500,638045608200] |