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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 43 |
| 5 | 207 |
| 6 | 2391 |
| 7 | 15539 |
| 8 | 182078 |
| 9 | 2070189 |
| 10 | 35850460 |
| 11 | 338695058 |
| 12 | 10609401552 |
| 13 | 115445915555 |
[1,1,2,8,43,207,2391,15539,182078,2070189, 35850460,338695058,10609401552,115445915555] |