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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 5 |
| 6 | 15 |
| 7 | 31 |
| 8 | 60 |
| 9 | 108 |
| 10 | 171 |
| 11 | 264 |
| 12 | 396 |
| 13 | 556 |
| 14 | 770 |
| 15 | 1050 |
| 16 | 1375 |
| 17 | 1785 |
| 18 | 2295 |
| 19 | 2880 |
| 20 | 3600 |
| 21 | 4425 |
| 22 | 5395 |
[1,5,15,31,60,108,171,264,396,556,770,1050,1375, 1785,2295,2880,3600,4425,5395] |