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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 6 |
| 4 | 21 |
| 5 | 82 |
| 6 | 399 |
| 7 | 2198 |
| 8 | 13769 |
| 9 | 96514 |
| 10 | 741659 |
| 11 | 6271430 |
| 12 | 57131613 |
| 13 | 564082066 |
| 14 | 5940252647 |
| 15 | 66977636630 |
| 16 | 799946033937 |
| 17 | 10133856674178 |
| 18 | 135255348669235 |
| 19 | 1901070660453382 |
| 20 | 28024821142319397 |
[1,2,3,6,21,82,399,2198,13769,96514,741659, 6271430,57131613,564082066,5940252647,66977636630, 799946033937,10133856674178,135255348669235, 1901070660453382,28024821142319397] |