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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 75 |
| 6 | 260 |
| 7 | 869 |
| 8 | 2817 |
| 9 | 8920 |
| 10 | 27745 |
| 11 | 85113 |
| 12 | 258256 |
| 13 | 776717 |
| 14 | 2319093 |
| 15 | 6882432 |
| 16 | 20321017 |
| 17 | 59738793 |
| 18 | 174960544 |
| 19 | 510756501 |
| 20 | 1486819229 |
| 21 | 4317417984 |
| 22 | 12509488161 |
| 23 | 36175413601 |
| 24 | 104433440896 |
| 25 | 301022300573 |
| 26 | 866485007957 |
[1,2,6,21,75,260,869,2817,8920,27745,85113,258256, 776717,2319093,6882432,20321017,59738793, 174960544,510756501,1486819229,4317417984, 12509488161,36175413601,104433440896,301022300573, 866485007957] |