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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 15 |
| 6 | 70 |
| 7 | 154 |
| 8 | 105 |
| 9 | 77 |
| 10 | 55 |
| 11 | 165 |
| 12 | 120 |
| 13 | 4620 |
| 14 | 62216 |
| 15 | 95445 |
| 16 | 72720 |
| 17 | 28280 |
| 18 | 43632 |
| 19 | 239976 |
| 20 | 3563280 |
| 21 | 2820930 |
| 22 | 372362760 |
| 23 | 37310748552 |
| 24 | 7078607624 |
| 25 | 10642043052900 |
| 26 | 2456049068550 |
| 27 | 17265042532279080 |
| 28 | 472434345656000280 |
| 29 | 22811829833104013520 |
[1,1,2,3,15,70,154,105,77,55,165,120,4620,62216, 95445,72720,28280,43632,239976,3563280,2820930, 372362760,37310748552,7078607624,10642043052900, 2456049068550,17265042532279080, 472434345656000280,22811829833104013520] |