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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 37 |
| 5 | 133 |
| 6 | 479 |
| 7 | 1719 |
| 8 | 6121 |
| 9 | 21609 |
| 10 | 75675 |
| 11 | 263171 |
| 12 | 909899 |
| 13 | 3130963 |
| 14 | 10730891 |
| 15 | 36639987 |
| 16 | 124528283 |
| 17 | 420319907 |
| 18 | 1403656123 |
| 19 | 4615627555 |
| 20 | 14868713515 |
| 21 | 46702912307 |
| 22 | 142489152555 |
| 23 | 421113970835 |
| 24 | 1203581558011 |
[1,1,3,11,37,133,479,1719,6121,21609,75675,263171, 909899,3130963,10730891,36639987,124528283, 420319907,1403656123,4615627555,14868713515, 46702912307,142489152555,421113970835, 1203581558011] |