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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 19 |
| 5 | 64 |
| 6 | 227 |
| 7 | 832 |
| 8 | 3126 |
| 9 | 11980 |
| 10 | 46646 |
| 11 | 184003 |
| 12 | 733783 |
| 13 | 2953434 |
| 14 | 11982265 |
| 15 | 48949631 |
| 16 | 201182110 |
| 17 | 831292029 |
| 18 | 3451336467 |
| 19 | 14390479996 |
| 20 | 60232976244 |
| 21 | 252992172572 |
| 22 | 1066000599632 |
| 23 | 4504710385216 |
| 24 | 19086728370308 |
| 25 | 81069926894797 |
[1,1,2,6,19,64,227,832,3126,11980,46646,184003, 733783,2953434,11982265,48949631,201182110, 831292029,3451336467,14390479996,60232976244, 252992172572,1066000599632,4504710385216, 19086728370308,81069926894797] |