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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 91 |
| 3 | 989 |
| 4 | 5396 |
| 5 | 117719 |
| 6 | 1284121 |
| 7 | 7003804 |
| 8 | 152799571 |
| 9 | 1666787669 |
| 10 | 9090932396 |
| 11 | 198333725039 |
| 12 | 2163489110641 |
| 13 | 11800023246004 |
| 14 | 257437022301451 |
| 15 | 2808207198823949 |
| 16 | 15316421082380996 |
| 17 | 334153056613557959 |
| 18 | 3645050780584375561 |
[4,91,989,5396,117719,1284121,7003804,152799571, 1666787669,9090932396,198333725039,2163489110641, 11800023246004,257437022301451,2808207198823949, 15316421082380996,334153056613557959, 3645050780584375561] |