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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 12 |
| 5 | 40 |
| 6 | 120 |
| 7 | 126 |
| 8 | 252 |
| 9 | 880 |
| 10 | 2520 |
| 11 | 2640 |
| 12 | 10880 |
| 13 | 30240 |
| 14 | 32640 |
| 15 | 37800 |
| 16 | 37926 |
| 17 | 55440 |
| 18 | 75852 |
| 19 | 685440 |
| 20 | 758520 |
| 21 | 831600 |
| 22 | 2600640 |
| 23 | 5533920 |
| 24 | 6917400 |
| 25 | 9102240 |
| 26 | 10281600 |
| 27 | 11377800 |
| 28 | 16687440 |
| 29 | 152182800 |
| 30 | 206317440 |
| 31 | 250311600 |
| 32 | 475917120 |
| 33 | 715816960 |
| 34 | 866829600 |
[1,2,6,12,40,120,126,252,880,2520,2640,10880, 30240,32640,37800,37926,55440,75852,685440,758520, 831600,2600640,5533920,6917400,9102240,10281600, 11377800,16687440,152182800,206317440,250311600, 475917120,715816960,866829600] |