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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 31 |
| 4 | 241 |
| 5 | 2021 |
| 6 | 19741 |
| 7 | 224155 |
| 8 | 2816801 |
| 9 | 38127241 |
| 10 | 557512021 |
| 11 | 8805585911 |
| 12 | 148896471505 |
| 13 | 2668912291501 |
| 14 | 50505733789421 |
| 15 | 1007422798667251 |
| 16 | 21118304040298561 |
| 17 | 463416656527980305 |
| 18 | 10612758078821689381 |
| 19 | 253157568544420465231 |
| 20 | 6279192326923499850161 |
[1,1,5,31,241,2021,19741,224155,2816801,38127241, 557512021,8805585911,148896471505,2668912291501, 50505733789421,1007422798667251,21118304040298561, 463416656527980305,10612758078821689381, 253157568544420465231,6279192326923499850161] |