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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 3 |
| 2 | 7 |
| 3 | 12 |
| 4 | 31 |
| 5 | 55 |
| 6 | 152 |
| 7 | 273 |
| 8 | 790 |
| 9 | 1428 |
| 10 | 4271 |
| 11 | 7752 |
| 12 | 23767 |
| 13 | 43263 |
| 14 | 135221 |
| 15 | 46675 |
| 16 | 782968 |
| 17 | 1430715 |
| 18 | 4598804 |
| 19 | 8414640 |
| 20 | 27332956 |
| 21 | 50067108 |
| 22 | 164081764 |
[2,3,7,12,31,55,152,273,790,1428,4271,7752,23767, 43263,135221,46675,782968,1430715,4598804,8414640, 27332956,50067108,164081764] |