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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 12 |
| 3 | 32 |
| 4 | 110 |
| 5 | 310 |
| 6 | 920 |
| 7 | 2558 |
| 8 | 7177 |
| 9 | 19660 |
| 10 | 53864 |
| 11 | 146180 |
| 12 | 396296 |
| 13 | 1070296 |
| 14 | 2888662 |
| 15 | 7785856 |
| 16 | 20982905 |
| 17 | 56536762 |
| 18 | 152378548 |
| 19 | 410825678 |
| 20 | 1108224556 |
| 21 | 2991244712 |
| 22 | 8079252116 |
| 23 | 21837144430 |
| 24 | 59066580606 |
| 25 | 159886668880 |
| 26 | 433122375508 |
[1,2,12,32,110,310,920,2558,7177,19660,53864, 146180,396296,1070296,2888662,7785856,20982905, 56536762,152378548,410825678,1108224556, 2991244712,8079252116,21837144430,59066580606, 159886668880,433122375508] |