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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 11 |
| 3 | 63 |
| 4 | 259 |
| 5 | 896 |
| 6 | 2821 |
| 7 | 8515 |
| 8 | 24940 |
| 9 | 70944 |
| 10 | 196626 |
| 11 | 534162 |
| 12 | 1430008 |
| 13 | 3786133 |
| 14 | 9937397 |
| 15 | 25902833 |
| 16 | 67151065 |
| 17 | 173338487 |
| 18 | 445930356 |
| 19 | 1144130515 |
| 20 | 2929289696 |
| 21 | 7487194973 |
[1,11,63,259,896,2821,8515,24940,70944,196626, 534162,1430008,3786133,9937397,25902833,67151065, 173338487,445930356,1144130515,2929289696, 7487194973] |