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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 32 |
| 5 | 133 |
| 6 | 625 |
| 7 | 3328 |
| 8 | 20172 |
| 9 | 137073 |
| 10 | 1023610 |
| 11 | 8327069 |
| 12 | 73711863 |
| 13 | 707141074 |
| 14 | 7278630390 |
| 15 | 79522233635 |
| 16 | 916354807657 |
| 17 | 11119419230485 |
| 18 | 142082222254701 |
| 19 | 1908850117706652 |
| 20 | 26862951637197372 |
| 21 | 394233330125117457 |
| 22 | 6013602782397882264 |
| 23 | 95208871146458467659 |
[1,1,3,9,32,133,625,3328,20172,137073,1023610, 8327069,73711863,707141074,7278630390,79522233635, 916354807657,11119419230485,142082222254701, 1908850117706652,26862951637197372, 394233330125117457,6013602782397882264, 95208871146458467659] |