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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 61 |
| 4 | 663 |
| 5 | 8793 |
| 6 | 73197 |
| 7 | 377856 |
| 8 | 8482203 |
| 9 | 42675876 |
| 10 | 800704143 |
| 11 | 4413365046 |
| 12 | 67209108462 |
| 13 | 851679188406 |
| 14 | 4565962115667 |
| 15 | 30014095639014 |
| 16 | 621157068621072 |
| 17 | 6758698456529694 |
| 18 | 64276780168282806 |
| 19 | 844262643142412415 |
[2,4,61,663,8793,73197,377856,8482203,42675876, 800704143,4413365046,67209108462,851679188406, 4565962115667,30014095639014,621157068621072, 6758698456529694,64276780168282806, 844262643142412415] |