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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 15 |
| 5 | 33 |
| 6 | 63 |
| 7 | 75 |
| 8 | 225 |
| 9 | 243 |
| 10 | 273 |
| 11 | 453 |
| 12 | 813 |
| 13 | 1275 |
| 14 | 1443 |
| 15 | 2763 |
| 16 | 3003 |
| 17 | 6693 |
| 18 | 9933 |
| 19 | 10515 |
[1,3,9,15,33,63,75,225,243,273,453,813,1275,1443, 2763,3003,6693,9933,10515] |