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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 41 |
| 4 | 250 |
| 5 | 1757 |
| 6 | 13917 |
| 7 | 122166 |
| 8 | 1173662 |
| 9 | 12222605 |
| 10 | 136927351 |
| 11 | 1639768418 |
| 12 | 20880556880 |
| 13 | 281460326864 |
| 14 | 4000651782511 |
| 15 | 59761935358025 |
| 16 | 935445106491702 |
| 17 | 15303039199768237 |
| 18 | 261030618751031385 |
| 19 | 4632889302298054713 |
[1,2,8,41,250,1757,13917,122166,1173662,12222605, 136927351,1639768418,20880556880,281460326864, 4000651782511,59761935358025,935445106491702, 15303039199768237,261030618751031385, 4632889302298054713] |