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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 5 |
| 5 | 7 |
| 6 | 19 |
| 7 | 39 |
| 8 | 121 |
| 9 | 321 |
| 10 | 813 |
| 11 | 2063 |
| 12 | 4957 |
| 13 | 11731 |
| 14 | 26329 |
| 15 | 59501 |
| 16 | 132273 |
| 17 | 294475 |
| 18 | 644557 |
| 19 | 1392933 |
| 20 | 2982557 |
[1,2,4,5,7,19,39,121,321,813,2063,4957,11731, 26329,59501,132273,294475,644557,1392933,2982557] |