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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 15 |
| 4 | 110 |
| 5 | 1051 |
| 6 | 10636 |
| 7 | 113290 |
| 8 | 1234189 |
| 9 | 13674761 |
| 10 | 153289285 |
[1,2,15,110,1051,10636,113290,1234189,13674761, 153289285] |