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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 46 |
| 5 | 166 |
| 6 | 610 |
| 7 | 2269 |
| 8 | 8518 |
| 9 | 32206 |
| 10 | 122464 |
| 11 | 467842 |
| 12 | 1794196 |
| 13 | 6903352 |
| 14 | 26635774 |
| 15 | 103020253 |
| 16 | 399300166 |
| 17 | 1550554582 |
| 18 | 6031074184 |
| 19 | 23493410758 |
| 20 | 91638191236 |
| 21 | 357874310212 |
| 22 | 1399137067684 |
| 23 | 5475504511858 |
| 24 | 21447950506396 |
[1,1,4,13,46,166,610,2269,8518,32206,122464, 467842,1794196,6903352,26635774,103020253, 399300166,1550554582,6031074184,23493410758, 91638191236,357874310212,1399137067684, 5475504511858,21447950506396] |