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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 8 |
| 5 | 20 |
| 6 | 58 |
| 7 | 179 |
| 8 | 576 |
| 9 | 1902 |
| 10 | 6426 |
| 11 | 22092 |
| 12 | 77026 |
| 13 | 271702 |
| 14 | 967840 |
| 15 | 3476555 |
| 16 | 12578728 |
| 17 | 45800278 |
| 18 | 167693698 |
| 19 | 617037126 |
| 20 | 2280467586 |
| 21 | 8461771342 |
| 22 | 31510700712 |
| 23 | 117725789124 |
| 24 | 441141656810 |
| 25 | 1657559677646 |
| 26 | 6243810767912 |
[1,1,2,3,8,20,58,179,576,1902,6426,22092,77026, 271702,967840,3476555,12578728,45800278,167693698, 617037126,2280467586,8461771342,31510700712, 117725789124,441141656810,1657559677646, 6243810767912] |