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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 16 |
| 6 | 84 |
| 7 | 403 |
| 8 | 3028 |
| 9 | 25431 |
| 10 | 250377 |
| 11 | 2726361 |
| 12 | 32622807 |
| 13 | 423310642 |
| 14 | 5921052187 |
| 15 | 88759485250 |
| 16 | 1419511438134 |
| 17 | 24123164524402 |
| 18 | 434094104795638 |
| 19 | 8245872981392311 |
| 20 | 164885609163058430 |
| 21 | 3462034812141768953 |
| 22 | 76154237902292661820 |
| 23 | 1751339843001023621169 |
[1,0,1,2,7,16,84,403,3028,25431,250377,2726361, 32622807,423310642,5921052187,88759485250, 1419511438134,24123164524402,434094104795638, 8245872981392311,164885609163058430, 3462034812141768953,76154237902292661820, 1751339843001023621169] |