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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 16 |
| 5 | 38 |
| 6 | 103 |
| 7 | 268 |
| 8 | 738 |
| 9 | 2029 |
| 10 | 5723 |
| 11 | 16242 |
| 12 | 46762 |
| 13 | 135584 |
| 14 | 396702 |
| 15 | 1167986 |
| 16 | 3460931 |
| 17 | 10308313 |
| 18 | 30853232 |
| 19 | 92734392 |
| 20 | 279811894 |
| 21 | 847218649 |
| 22 | 2573387068 |
| 23 | 7839150746 |
| 24 | 23943472360 |
| 25 | 73310409148 |
| 26 | 224970044407 |
| 27 | 691817432334 |
[1,1,3,6,16,38,103,268,738,2029,5723,16242,46762, 135584,396702,1167986,3460931,10308313,30853232, 92734392,279811894,847218649,2573387068, 7839150746,23943472360,73310409148,224970044407, 691817432334] |