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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 66 |
| 4 | 560 |
| 5 | 5770 |
| 6 | 69852 |
| 7 | 970886 |
| 8 | 15228880 |
| 9 | 266006610 |
| 10 | 5119447700 |
| 11 | 107617719022 |
| 12 | 2453167135608 |
| 13 | 60268223308826 |
| 14 | 1587381621990556 |
| 15 | 44619277892537910 |
| 16 | 1333135910963656352 |
| 17 | 42189279001183102882 |
| 18 | 1409741875877923927332 |
| 19 | 49597905017847180008126 |
[1,2,10,66,560,5770,69852,970886,15228880, 266006610,5119447700,107617719022,2453167135608, 60268223308826,1587381621990556,44619277892537910, 1333135910963656352,42189279001183102882, 1409741875877923927332,49597905017847180008126] |