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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 15 |
| 6 | 28 |
| 7 | 52 |
| 8 | 96 |
| 9 | 177 |
| 10 | 326 |
| 11 | 600 |
| 12 | 1104 |
| 13 | 2031 |
| 14 | 3736 |
| 15 | 6872 |
| 16 | 12640 |
| 17 | 23249 |
[0,1,2,4,8,15,28,52,96,177,326,600,1104,2031,3736, 6872,12640,23249] |