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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 57 |
| 5 | 224 |
| 6 | 1038 |
| 7 | 4459 |
| 8 | 21206 |
| 9 | 95450 |
| 10 | 460768 |
| 11 | 2133473 |
| 12 | 10395594 |
| 13 | 49032011 |
| 14 | 240409450 |
| 15 | 1148482686 |
| 16 | 5655779024 |
| 17 | 27268079722 |
| 18 | 134709037376 |
| 19 | 653917834101 |
| 20 | 3238092590185 |
| 21 | 15800643148860 |
| 22 | 78382843357317 |
| 23 | 384029211313430 |
| 24 | 1907725906035345 |
| 25 | 9376714816549434 |
| 26 | 46631525727999251 |
| 27 | 229790507773596674 |
[1,1,4,13,57,224,1038,4459,21206,95450,460768, 2133473,10395594,49032011,240409450,1148482686, 5655779024,27268079722,134709037376,653917834101, 3238092590185,15800643148860,78382843357317, 384029211313430,1907725906035345,9376714816549434, 46631525727999251,229790507773596674] |