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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 1803 |
| 4 | 2015052 |
| 5 | 20582691507 |
| 6 | 1928747601908977 |
| 7 | 1657680158728377785062 |
| 8 | 13067714049552363383420892169 |
| 9 | 944866406096482421853329114821597865 |
[1,15,1803,2015052,20582691507,1928747601908977, 1657680158728377785062, 13067714049552363383420892169, 944866406096482421853329114821597865] |