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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 36 |
| 6 | 109 |
| 7 | 340 |
| 8 | 1116 |
| 9 | 3744 |
| 10 | 12981 |
| 11 | 45722 |
| 12 | 165247 |
| 13 | 603242 |
| 14 | 2242932 |
| 15 | 8422438 |
| 16 | 32040585 |
| 17 | 122800802 |
| 18 | 475937009 |
[1,1,2,5,13,36,109,340,1116,3744,12981,45722, 165247,603242,2242932,8422438,32040585,122800802, 475937009] |