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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 25 |
| 6 | 72 |
| 7 | 245 |
| 8 | 772 |
| 9 | 2692 |
| 10 | 8925 |
| 11 | 32065 |
| 12 | 109890 |
| 13 | 400023 |
| 14 | 1402723 |
| 15 | 5165327 |
| 16 | 18484746 |
| 17 | 68635477 |
| 18 | 248339122 |
| 19 | 930138521 |
| 20 | 3406231198 |
| 21 | 12810761323 |
| 22 | 47306348881 |
| 23 | 178987624513 |
| 24 | 665627041157 |
| 25 | 2528210175630 |
| 26 | 9456885664122 |
[1,1,3,8,25,72,245,772,2692,8925,32065,109890, 400023,1402723,5165327,18484746,68635477, 248339122,930138521,3406231198,12810761323, 47306348881,178987624513,665627041157, 2528210175630,9456885664122] |