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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 7 |
| 7 | 17 |
| 8 | 40 |
| 9 | 101 |
| 10 | 259 |
| 11 | 671 |
| 12 | 1741 |
| 13 | 4689 |
| 14 | 12511 |
| 15 | 33603 |
| 16 | 91249 |
[1,0,1,2,4,7,17,40,101,259,671,1741,4689,12511, 33603,91249] |