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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 13 |
| 3 | 86 |
| 4 | 375 |
| 5 | 2289 |
| 6 | 12807 |
| 7 | 79376 |
| 8 | 487669 |
| 9 | 3112659 |
| 10 | 20011341 |
| 11 | 131002051 |
| 12 | 865156193 |
| 13 | 5775171729 |
| 14 | 38841026305 |
| 15 | 263161175842 |
| 16 | 1793749636759 |
| 17 | 12294401226021 |
| 18 | 84671929129311 |
| 19 | 585688412266001 |
| 20 | 4067110924673259 |
[1,8,13,86,375,2289,12807,79376,487669,3112659, 20011341,131002051,865156193,5775171729, 38841026305,263161175842,1793749636759, 12294401226021,84671929129311,585688412266001, 4067110924673259] |