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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 49 |
| 5 | 301 |
| 6 | 2161 |
| 7 | 17641 |
| 8 | 161281 |
| 9 | 1632961 |
| 10 | 18144001 |
| 11 | 219542401 |
| 12 | 2874009601 |
| 13 | 40475635201 |
| 14 | 610248038401 |
| 15 | 9807557760001 |
| 16 | 167382319104001 |
| 17 | 3023343138816001 |
| 18 | 57621363351552001 |
| 19 | 1155628453883904001 |
| 20 | 24329020081766400001 |
[1,3,10,49,301,2161,17641,161281,1632961,18144001, 219542401,2874009601,40475635201,610248038401, 9807557760001,167382319104001,3023343138816001, 57621363351552001,1155628453883904001, 24329020081766400001] |