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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 40 |
| 5 | 204 |
| 6 | 1227 |
| 7 | 8591 |
| 8 | 68729 |
| 9 | 618567 |
| 10 | 6185670 |
| 11 | 68042371 |
| 12 | 816508457 |
| 13 | 10614609952 |
| 14 | 148604539330 |
| 15 | 2229068089950 |
| 16 | 35665089439210 |
| 17 | 606306520466578 |
| 18 | 10913517368398413 |
| 19 | 207356829999569855 |
| 20 | 4147136599991397105 |
[1,3,10,40,204,1227,8591,68729,618567,6185670, 68042371,816508457,10614609952,148604539330, 2229068089950,35665089439210,606306520466578, 10913517368398413,207356829999569855, 4147136599991397105] |