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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 6 |
| 5 | 14 |
| 6 | 42 |
| 7 | 122 |
| 8 | 382 |
| 9 | 1206 |
| 10 | 3922 |
| 11 | 12914 |
| 12 | 43190 |
| 13 | 145950 |
| 14 | 498170 |
| 15 | 1714026 |
| 16 | 5940014 |
| 17 | 20712646 |
| 18 | 72623266 |
| 19 | 255875298 |
| 20 | 905477734 |
| 21 | 3216853294 |
| 22 | 11469069258 |
| 23 | 41023019098 |
| 24 | 147166210014 |
| 25 | 529374272470 |
| 26 | 1908965352434 |
| 27 | 6899707805522 |
| 28 | 24991194656022 |
| 29 | 90698707816766 |
[1,2,2,6,14,42,122,382,1206,3922,12914,43190, 145950,498170,1714026,5940014,20712646,72623266, 255875298,905477734,3216853294,11469069258, 41023019098,147166210014,529374272470, 1908965352434,6899707805522,24991194656022, 90698707816766] |