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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 21 |
| 3 | 35 |
| 4 | 35 |
| 5 | 90 |
| 6 | 140 |
| 7 | 189 |
| 8 | 210 |
| 9 | 280 |
| 10 | 280 |
| 11 | 280 |
| 12 | 280 |
| 13 | 315 |
| 14 | 315 |
| 15 | 420 |
| 16 | 560 |
| 17 | 640 |
| 18 | 640 |
| 19 | 729 |
| 20 | 896 |
[1,21,35,35,90,140,189,210,280,280,280,280,315, 315,420,560,640,640,729,896] |