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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 5 |
| 4 | 19 |
| 5 | 75 |
| 6 | 287 |
| 7 | 1053 |
| 8 | 3859 |
| 9 | 14089 |
| 10 | 51463 |
| 11 | 188697 |
| 12 | 695155 |
| 13 | 2573235 |
| 14 | 9571195 |
| 15 | 35759799 |
| 16 | 134154259 |
| 17 | 505163055 |
| 18 | 1908619755 |
| 19 | 7233118641 |
| 20 | 27486768415 |
| 21 | 104713346699 |
| 22 | 399818311219 |
| 23 | 1529747101965 |
| 24 | 5864045590035 |
| 25 | 22517965253595 |
| 26 | 86607619323751 |
| 27 | 333599840675337 |
[1,5,19,75,287,1053,3859,14089,51463,188697, 695155,2573235,9571195,35759799,134154259, 505163055,1908619755,7233118641,27486768415, 104713346699,399818311219,1529747101965, 5864045590035,22517965253595,86607619323751, 333599840675337] |