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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 22 |
| 4 | 261 |
| 5 | 4186 |
| 6 | 85035 |
| 7 | 2096242 |
| 8 | 60793257 |
| 9 | 2028053146 |
| 10 | 76512294567 |
| 11 | 3221179205410 |
| 12 | 149713378082301 |
| 13 | 7614267616582810 |
| 14 | 420634056602820099 |
| 15 | 25081994054279063506 |
| 16 | 1605673188973569254481 |
| 17 | 109838361160586478627226 |
| 18 | 7995918540574019507985471 |
[1,1,3,22,261,4186,85035,2096242,60793257, 2028053146,76512294567,3221179205410, 149713378082301,7614267616582810, 420634056602820099,25081994054279063506, 1605673188973569254481,109838361160586478627226, 7995918540574019507985471] |