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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 8 |
| 4 | 23 |
| 5 | 70 |
| 6 | 230 |
| 7 | 782 |
| 8 | 2729 |
| 9 | 9740 |
| 10 | 35345 |
| 11 | 130018 |
| 12 | 483782 |
| 13 | 1817450 |
| 14 | 6884050 |
| 15 | 26261498 |
| 16 | 100808873 |
| 17 | 389101464 |
| 18 | 1509198827 |
| 19 | 5879305034 |
| 20 | 22993849657 |
[1,2,3,8,23,70,230,782,2729,9740,35345,130018, 483782,1817450,6884050,26261498,100808873, 389101464,1509198827,5879305034,22993849657] |