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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 29 |
| 6 | 85 |
| 7 | 254 |
| 8 | 762 |
| 9 | 2285 |
| 10 | 6854 |
| 11 | 20562 |
| 12 | 61684 |
| 13 | 185052 |
| 14 | 555154 |
| 15 | 1665461 |
[1,2,4,10,29,85,254,762,2285,6854,20562,61684, 185052,555154,1665461] |