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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 52 |
| 4 | 459 |
| 5 | 5526 |
| 6 | 91161 |
| 7 | 2039024 |
| 8 | 62264215 |
| 9 | 2618031658 |
| 10 | 153147765333 |
| 11 | 12544274587956 |
| 12 | 1443661355799075 |
| 13 | 233590364506712318 |
| 14 | 53152637809972391281 |
| 15 | 17010099259539378971368 |
| 16 | 7660283773351147860024879 |
| 17 | 4856904906875123474086041426 |
[1,2,9,52,459,5526,91161,2039024,62264215, 2618031658,153147765333,12544274587956, 1443661355799075,233590364506712318, 53152637809972391281,17010099259539378971368, 7660283773351147860024879, 4856904906875123474086041426] |