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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 43 |
| 5 | 317 |
| 6 | 4395 |
| 7 | 85883 |
| 8 | 3189035 |
| 9 | 155707292 |
| 10 | 14992855085 |
| 11 | 1844750664909 |
| 12 | 446183107764907 |
| 13 | 140966932321586720 |
[1,2,7,43,317,4395,85883,3189035,155707292, 14992855085,1844750664909,446183107764907, 140966932321586720] |