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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 6 |
| 5 | 10 |
| 6 | 18 |
| 7 | 22 |
| 8 | 30 |
| 9 | 42 |
| 10 | 58 |
| 11 | 70 |
| 12 | 78 |
| 13 | 102 |
| 14 | 130 |
| 15 | 190 |
| 16 | 210 |
| 17 | 330 |
| 18 | 462 |
[1,2,4,6,10,18,22,30,42,58,70,78,102,130,190,210, 330,462] |