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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 21 |
| 5 | 59 |
| 6 | 232 |
| 7 | 794 |
| 8 | 3336 |
| 9 | 12721 |
| 10 | 55573 |
| 11 | 226145 |
| 12 | 1014025 |
| 13 | 4308738 |
| 14 | 19687857 |
| 15 | 86260599 |
| 16 | 399772916 |
| 17 | 1791614525 |
| 18 | 8394315873 |
| 19 | 38270944739 |
| 20 | 180858444718 |
| 21 | 835634742240 |
| 22 | 3976262762887 |
| 23 | 18567287661392 |
| 24 | 88846974815848 |
| 25 | 418431425333779 |
| 26 | 2011553532742219 |
| 27 | 9540027225361458 |
| 28 | 46040658044984744 |
[1,1,3,6,21,59,232,794,3336,12721,55573,226145, 1014025,4308738,19687857,86260599,399772916, 1791614525,8394315873,38270944739,180858444718, 835634742240,3976262762887,18567287661392, 88846974815848,418431425333779,2011553532742219, 9540027225361458,46040658044984744] |