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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 71 |
| 5 | 214 |
| 6 | 644 |
| 7 | 1934 |
| 8 | 5803 |
| 9 | 17411 |
| 10 | 52235 |
| 11 | 156706 |
| 12 | 470120 |
| 13 | 1410362 |
| 14 | 4231087 |
| 15 | 12693263 |
| 16 | 38079791 |
| 17 | 114239374 |
| 18 | 342718124 |
| 19 | 1028154374 |
| 20 | 3084463123 |
| 21 | 9253389371 |
| 22 | 27760168115 |
| 23 | 83280504346 |
| 24 | 249841513040 |
| 25 | 749524539122 |
[2,7,23,71,214,644,1934,5803,17411,52235,156706, 470120,1410362,4231087,12693263,38079791, 114239374,342718124,1028154374,3084463123, 9253389371,27760168115,83280504346,249841513040, 749524539122] |