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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 20 |
| 2 | 449 |
| 3 | 6792 |
| 4 | 67063 |
| 5 | 484419 |
| 6 | 2750715 |
| 7 | 12919671 |
| 8 | 52083292 |
| 9 | 185179593 |
| 10 | 592791088 |
| 11 | 1736022657 |
| 12 | 4710111660 |
| 13 | 11959634412 |
| 14 | 28654640036 |
| 15 | 65224656452 |
| 16 | 141850935657 |
| 17 | 296163412400 |
| 18 | 596041392921 |
| 19 | 1160330645548 |
| 20 | 2191579277799 |
| 21 | 4026627536451 |
| 22 | 7213267409435 |
[1,20,449,6792,67063,484419,2750715,12919671, 52083292,185179593,592791088,1736022657, 4710111660,11959634412,28654640036,65224656452, 141850935657,296163412400,596041392921, 1160330645548,2191579277799,4026627536451, 7213267409435] |