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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 15 |
| 6 | 70 |
| 7 | 330 |
| 8 | 1820 |
| 9 | 10858 |
| 10 | 70875 |
| 11 | 497135 |
| 12 | 3727955 |
| 13 | 29658410 |
| 14 | 248989676 |
| 15 | 2194891440 |
| 16 | 20231692430 |
| 17 | 194286848280 |
| 18 | 1937546532820 |
| 19 | 20008993160460 |
| 20 | 213436182918652 |
| 21 | 2346406693816315 |
| 22 | 26531060178217182 |
| 23 | 307987244037724262 |
| 24 | 3664579007885995952 |
[1,0,1,1,5,15,70,330,1820,10858,70875,497135, 3727955,29658410,248989676,2194891440,20231692430, 194286848280,1937546532820,20008993160460, 213436182918652,2346406693816315, 26531060178217182,307987244037724262, 3664579007885995952] |