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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 41 |
| 6 | 231 |
| 7 | 1551 |
| 8 | 12037 |
| 9 | 105861 |
| 10 | 1039539 |
| 11 | 11268059 |
| 12 | 133585089 |
| 13 | 1718984673 |
| 14 | 23857531519 |
| 15 | 355190381031 |
| 16 | 5646040979901 |
| 17 | 95432906354621 |
| 18 | 1709068974897867 |
| 19 | 32325104169244851 |
| 20 | 643869687410800249 |
| 21 | 13471540400560532889 |
| 22 | 295384662114697463319 |
[1,3,9,41,231,1551,12037,105861,1039539,11268059, 133585089,1718984673,23857531519,355190381031, 5646040979901,95432906354621,1709068974897867, 32325104169244851,643869687410800249, 13471540400560532889,295384662114697463319] |