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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 2 |
| 6 | 6 |
| 7 | 14 |
| 8 | 40 |
| 9 | 120 |
| 10 | 389 |
| 11 | 1355 |
| 12 | 5040 |
| 13 | 19884 |
| 14 | 82834 |
| 15 | 362880 |
| 16 | 1665837 |
| 17 | 7988887 |
| 18 | 39916800 |
| 19 | 207304278 |
| 20 | 1116669003 |
| 21 | 6227020800 |
| 22 | 35886673906 |
| 23 | 213407853922 |
| 24 | 1307674368000 |
| 25 | 8245960182038 |
| 26 | 53446811415729 |
| 27 | 355687428096000 |
| 28 | 2427977164711192 |
| 29 | 16984208960998389 |
[1,0,1,1,2,6,14,40,120,389,1355,5040,19884,82834, 362880,1665837,7988887,39916800,207304278, 1116669003,6227020800,35886673906,213407853922, 1307674368000,8245960182038,53446811415729, 355687428096000,2427977164711192, 16984208960998389] |