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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 95 |
| 5 | 376 |
| 6 | 1523 |
| 7 | 6290 |
| 8 | 26373 |
| 9 | 111886 |
| 10 | 479365 |
| 11 | 2070771 |
| 12 | 9008071 |
| 13 | 39423578 |
| 14 | 173448057 |
| 15 | 766653471 |
| 16 | 3402677801 |
| 17 | 15158156612 |
| 18 | 67751162313 |
| 19 | 303735992197 |
| 20 | 1365425697699 |
| 21 | 6153622483468 |
| 22 | 27796881592189 |
| 23 | 125830507827952 |
| 24 | 570731294883201 |
| 25 | 2593415906726304 |
| 26 | 11804642094167071 |
| 27 | 53817646415676925 |
[1,2,7,25,95,376,1523,6290,26373,111886,479365, 2070771,9008071,39423578,173448057,766653471, 3402677801,15158156612,67751162313,303735992197, 1365425697699,6153622483468,27796881592189, 125830507827952,570731294883201,2593415906726304, 11804642094167071,53817646415676925] |