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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 115 |
| 4 | 1175 |
| 5 | 13052 |
| 6 | 153115 |
| 7 | 1866599 |
| 8 | 23414063 |
| 9 | 300238945 |
| 10 | 3917984904 |
| 11 | 51862207151 |
| 12 | 694670871393 |
| 13 | 9398137507922 |
| 14 | 128235826442635 |
| 15 | 1762706644013297 |
| 16 | 24386388751113511 |
| 17 | 339295523459625535 |
| 18 | 4744546261930628062 |
| 19 | 66644485202547680010 |
| 20 | 939916204595095866644 |
[1,2,13,115,1175,13052,153115,1866599,23414063, 300238945,3917984904,51862207151,694670871393, 9398137507922,128235826442635,1762706644013297, 24386388751113511,339295523459625535, 4744546261930628062,66644485202547680010, 939916204595095866644] |