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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 5 |
| 6 | 8 |
| 7 | 40 |
| 8 | 96 |
| 9 | 297 |
| 10 | 1269 |
| 11 | 3456 |
| 12 | 12839 |
| 13 | 46691 |
| 14 | 153111 |
| 15 | 577167 |
| 16 | 2054576 |
| 17 | 7602937 |
| 18 | 29000337 |
| 19 | 110645967 |
| 20 | 418889453 |
| 21 | 1580667760 |
| 22 | 6058528796 |
| 23 | 23121913246 |
| 24 | 89793473393 |
| 25 | 350029321425 |
| 26 | 1359919742613 |
| 27 | 5340642744919 |
| 28 | 20948242218543 |
| 29 | 82505892314268 |
[1,1,0,0,1,5,8,40,96,297,1269,3456,12839,46691, 153111,577167,2054576,7602937,29000337,110645967, 418889453,1580667760,6058528796,23121913246, 89793473393,350029321425,1359919742613, 5340642744919,20948242218543,82505892314268] |