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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 9 |
| 3 | 64 |
| 4 | 441 |
| 5 | 3025 |
| 6 | 20736 |
| 7 | 142129 |
| 8 | 974169 |
| 9 | 6677056 |
| 10 | 45765225 |
| 11 | 313679521 |
| 12 | 2149991424 |
| 13 | 14736260449 |
| 14 | 101003831721 |
| 15 | 692290561600 |
| 16 | 4745030099481 |
| 17 | 32522920134769 |
| 18 | 222915410843904 |
| 19 | 1527884955772561 |
| 20 | 10472279279564025 |
| 21 | 71778070001175616 |
| 22 | 491974210728665289 |
[0,1,9,64,441,3025,20736,142129,974169,6677056, 45765225,313679521,2149991424,14736260449, 101003831721,692290561600,4745030099481, 32522920134769,222915410843904,1527884955772561, 10472279279564025,71778070001175616, 491974210728665289] |