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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 11 |
| 5 | 49 |
| 6 | 252 |
| 7 | 1406 |
| 8 | 8405 |
| 9 | 52348 |
| 10 | 337029 |
| 11 | 2225333 |
| 12 | 15002763 |
| 13 | 102896407 |
| 14 | 716106077 |
| 15 | 5046649182 |
| 16 | 35956186581 |
| 17 | 258649116963 |
| 18 | 1876462272125 |
| 19 | 13717081730294 |
| 20 | 100957850485311 |
| 21 | 747631534534529 |
| 22 | 5567459642741752 |
| 23 | 41671027665802639 |
| 24 | 313351688709886964 |
| 25 | 2366390596263188755 |
[1,1,1,3,11,49,252,1406,8405,52348,337029,2225333, 15002763,102896407,716106077,5046649182, 35956186581,258649116963,1876462272125, 13717081730294,100957850485311,747631534534529, 5567459642741752,41671027665802639, 313351688709886964,2366390596263188755] |