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| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 26 |
| 3 | 498 |
| 4 | 3422 |
| 5 | 27967 |
| 6 | 197308 |
| 7 | 1324860 |
| 8 | 8405212 |
| 9 | 51417327 |
| 10 | 303703636 |
| 11 | 1731421125 |
| 12 | 9525742325 |
| 13 | 50654533963 |
| 14 | 260914306516 |
| 15 | 1304341448963 |
| 16 | 6337774514024 |
| 17 | 29964888604613 |
| 18 | 137989085373438 |
| 19 | 619551753355165 |
[20,26,498,3422,27967,197308,1324860,8405212, 51417327,303703636,1731421125,9525742325, 50654533963,260914306516,1304341448963, 6337774514024,29964888604613,137989085373438, 619551753355165] |