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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 23 |
| 6 | 82 |
| 7 | 452 |
| 8 | 2369 |
| 9 | 18356 |
| 10 | 143308 |
| 11 | 1396222 |
| 12 | 13000455 |
| 13 | 152886068 |
[1,1,1,3,8,23,82,452,2369,18356,143308,1396222, 13000455,152886068] |