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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 7 |
| 3 | 15 |
| 4 | 20 |
| 5 | 31 |
| 6 | 37 |
| 7 | 56 |
| 8 | 70 |
| 9 | 95 |
| 10 | 113 |
| 11 | 162 |
| 12 | 193 |
| 13 | 264 |
| 14 | 310 |
| 15 | 415 |
| 16 | 486 |
| 17 | 640 |
| 18 | 741 |
| 19 | 950 |
| 20 | 1082 |
| 21 | 1374 |
| 22 | 1556 |
[4,7,15,20,31,37,56,70,95,113,162,193,264,310,415, 486,640,741,950,1082,1374,1556] |