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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 13 |
| 3 | 23 |
| 4 | 125 |
| 5 | 420 |
| 6 | 1943 |
| 7 | 9012 |
| 8 | 42321 |
| 9 | 205597 |
| 10 | 995518 |
| 11 | 4853006 |
| 12 | 23686103 |
| 13 | 115662456 |
| 14 | 565154846 |
| 15 | 2761642814 |
| 16 | 13496474311 |
| 17 | 65961394749 |
| 18 | 322378456355 |
| 19 | 1575606171809 |
| 20 | 7700708480150 |
| 21 | 37636981234967 |
| 22 | 183949803071588 |
[1,13,23,125,420,1943,9012,42321,205597,995518, 4853006,23686103,115662456,565154846,2761642814, 13496474311,65961394749,322378456355, 1575606171809,7700708480150,37636981234967, 183949803071588] |