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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 3 |
| 9 | 9 |
| 10 | 19 |
| 11 | 37 |
| 12 | 103 |
| 13 | 317 |
| 14 | 831 |
| 15 | 2581 |
| 16 | 12105 |
| 17 | 62053 |
| 18 | 307133 |
| 19 | 1586103 |
| 20 | 9856867 |
| 21 | 66841097 |
| 22 | 477861431 |
[1,1,1,1,1,1,1,3,9,19,37,103,317,831,2581,12105, 62053,307133,1586103,9856867,66841097,477861431] |