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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 61 |
| 6 | 361 |
| 7 | 1261 |
| 8 | 3361 |
| 9 | 128521 |
| 10 | 1678321 |
| 11 | 11670121 |
| 12 | 56596321 |
| 13 | 1773048421 |
| 14 | 37020623641 |
| 15 | 410615985781 |
| 16 | 3056256665281 |
| 17 | 88439609228881 |
| 18 | 2516514283997281 |
| 19 | 39513591769228561 |
| 20 | 409546654143301441 |
| 21 | 11679302565962651341 |
| 22 | 413008783534735181641 |
[1,1,1,1,1,61,361,1261,3361,128521,1678321, 11670121,56596321,1773048421,37020623641, 410615985781,3056256665281,88439609228881, 2516514283997281,39513591769228561, 409546654143301441,11679302565962651341, 413008783534735181641] |