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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 119 |
| 6 | 605 |
| 7 | 3597 |
| 8 | 24624 |
| 9 | 191481 |
| 10 | 1672273 |
| 11 | 16240509 |
| 12 | 173870156 |
| 13 | 2036293453 |
| 14 | 25910852669 |
| 15 | 356057435177 |
| 16 | 5255621683776 |
| 17 | 82932788545297 |
| 18 | 1393129225943169 |
| 19 | 24819194946609589 |
| 20 | 467369450831456492 |
| 21 | 9274872837974110805 |
| 22 | 193447045984755732413 |
[0,1,3,8,28,119,605,3597,24624,191481,1672273, 16240509,173870156,2036293453,25910852669, 356057435177,5255621683776,82932788545297, 1393129225943169,24819194946609589, 467369450831456492,9274872837974110805, 193447045984755732413] |