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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 38 |
| 6 | 295 |
| 7 | 3098 |
| 8 | 42271 |
| 9 | 726734 |
| 10 | 15366679 |
| 11 | 391888514 |
| 12 | 11860602415 |
| 13 | 420258768950 |
| 14 | 17233254330343 |
| 15 | 809698074358250 |
| 16 | 43212125903877439 |
| 17 | 2599512037272630686 |
| 18 | 175079893678534943287 |
| 19 | 13122303354155987156306 |
[1,1,2,7,38,295,3098,42271,726734,15366679, 391888514,11860602415,420258768950,17233254330343, 809698074358250,43212125903877439, 2599512037272630686,175079893678534943287, 13122303354155987156306] |