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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 8 |
| 5 | 20 |
| 6 | 80 |
| 7 | 210 |
| 8 | 672 |
| 9 | 2688 |
| 10 | 10080 |
| 11 | 44352 |
| 12 | 236544 |
| 13 | 960960 |
| 14 | 4324320 |
| 15 | 20270250 |
| 16 | 104247000 |
| 17 | 522762240 |
| 18 | 3024552960 |
| 19 | 15713497800 |
| 20 | 108973522944 |
| 21 | 625746401280 |
| 22 | 3824005785600 |
| 23 | 24049411386000 |
| 24 | 160329409240000 |
| 25 | 858907549500000 |
| 26 | 5226869622374400 |
[1,2,3,8,20,80,210,672,2688,10080,44352,236544, 960960,4324320,20270250,104247000,522762240, 3024552960,15713497800,108973522944,625746401280, 3824005785600,24049411386000,160329409240000, 858907549500000,5226869622374400] |