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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 72 |
| 6 | 233 |
| 7 | 739 |
| 8 | 2343 |
| 9 | 7458 |
| 10 | 23801 |
| 11 | 76016 |
| 12 | 242777 |
| 13 | 775265 |
| 14 | 2475513 |
| 15 | 7904587 |
| 16 | 25240597 |
| 17 | 80598107 |
| 18 | 257366469 |
| 19 | 821825201 |
| 20 | 2624260190 |
| 21 | 8379812195 |
| 22 | 26758495711 |
| 23 | 85445488885 |
| 24 | 272845382481 |
| 25 | 871252605664 |
| 26 | 2782092566535 |
[1,2,6,21,72,233,739,2343,7458,23801,76016,242777, 775265,2475513,7904587,25240597,80598107, 257366469,821825201,2624260190,8379812195, 26758495711,85445488885,272845382481,871252605664, 2782092566535] |