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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 10 |
| 3 | 21 |
| 4 | 64 |
| 5 | 219 |
| 6 | 589 |
| 7 | 1782 |
| 8 | 5621 |
| 9 | 17333 |
| 10 | 54199 |
| 11 | 169770 |
| 12 | 532625 |
| 13 | 1674674 |
| 14 | 5267287 |
| 15 | 16571936 |
| 16 | 52167148 |
| 17 | 164217643 |
| 18 | 517100360 |
| 19 | 1628230629 |
| 20 | 5127481455 |
| 21 | 16147257228 |
| 22 | 50851033975 |
| 23 | 160145034188 |
| 24 | 504341598687 |
| 25 | 1588336701913 |
| 26 | 5002186675765 |
[2,10,21,64,219,589,1782,5621,17333,54199,169770, 532625,1674674,5267287,16571936,52167148, 164217643,517100360,1628230629,5127481455, 16147257228,50851033975,160145034188,504341598687, 1588336701913,5002186675765] |