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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 24 |
| 6 | 98 |
| 7 | 622 |
| 8 | 7293 |
| 9 | 162052 |
| 10 | 6997100 |
| 11 | 578605618 |
| 12 | 90558592724 |
| 13 | 26673271109299 |
| 14 | 14758661765740616 |
[1,1,2,4,9,24,98,622,7293,162052,6997100, 578605618,90558592724,26673271109299, 14758661765740616] |