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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 6 |
| 6 | 7 |
| 7 | 8 |
| 8 | 15 |
| 9 | 36 |
| 10 | 38 |
| 11 | 51 |
| 12 | 168 |
| 13 | 1000 |
| 14 | 2955 |
| 15 | 8151 |
| 16 | 16456 |
| 17 | 17902 |
| 18 | 18784 |
| 19 | 24948 |
| 20 | 28731 |
| 21 | 87144 |
[0,1,2,3,6,7,8,15,36,38,51,168,1000,2955,8151, 16456,17902,18784,24948,28731,87144] |