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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 7 |
| 5 | 7 |
| 6 | 9 |
| 7 | 15 |
| 8 | 18 |
| 9 | 21 |
| 10 | 21 |
| 11 | 27 |
| 12 | 31 |
| 13 | 37 |
| 14 | 42 |
| 15 | 44 |
| 16 | 49 |
| 17 | 56 |
| 18 | 63 |
| 19 | 70 |
[1,3,6,7,7,9,15,18,21,21,27,31,37,42,44,49,56,63, 70] |