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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 19 |
| 6 | 79 |
| 7 | 454 |
| 8 | 2673 |
| 9 | 20789 |
| 10 | 159101 |
| 11 | 1568786 |
| 12 | 14804701 |
| 13 | 177333727 |
| 14 | 1991552627 |
| 15 | 28122135014 |
| 16 | 366398602529 |
| 17 | 5965436400009 |
| 18 | 88463085201433 |
| 19 | 1632635041751362 |
| 20 | 27151272591960661 |
| 21 | 560416797991873451 |
| 22 | 10329130452139887191 |
| 23 | 235856196146890193062 |
[1,1,1,2,5,19,79,454,2673,20789,159101,1568786, 14804701,177333727,1991552627,28122135014, 366398602529,5965436400009,88463085201433, 1632635041751362,27151272591960661, 560416797991873451,10329130452139887191, 235856196146890193062] |