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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 20 |
| 3 | 35 |
| 4 | 143 |
| 5 | 208 |
| 6 | 2623 |
| 7 | 5183 |
| 8 | 27796 |
| 9 | 11177983 |
| 10 | 69677008 |
| 11 | 920158207 |
| 12 | 1099508482048 |
[1,20,35,143,208,2623,5183,27796,11177983, 69677008,920158207,1099508482048] |