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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 5 |
| 6 | 15 |
| 7 | 20 |
| 8 | 27 |
| 9 | 47 |
| 10 | 81 |
| 11 | 121 |
| 12 | 129 |
| 13 | 281 |
| 14 | 303 |
| 15 | 4601 |
| 16 | 12983 |
| 17 | 13613 |
| 18 | 42760 |
| 19 | 90595 |
| 20 | 109927 |
| 21 | 158241 |
[0,1,2,3,5,15,20,27,47,81,121,129,281,303,4601, 12983,13613,42760,90595,109927,158241] |