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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 20 |
| 6 | 57 |
| 7 | 119 |
| 8 | 329 |
| 9 | 760 |
| 10 | 1942 |
| 11 | 4452 |
| 12 | 13574 |
| 13 | 30665 |
| 14 | 80117 |
| 15 | 194856 |
| 16 | 540694 |
[1,1,2,4,10,20,57,119,329,760,1942,4452,13574, 30665,80117,194856,540694] |