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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 99 |
| 5 | 403 |
| 6 | 1719 |
| 7 | 7451 |
| 8 | 33116 |
| 9 | 148742 |
| 10 | 678430 |
| 11 | 3117059 |
| 12 | 14468349 |
| 13 | 67515160 |
| 14 | 317323787 |
| 15 | 1497442597 |
| 16 | 7103751478 |
| 17 | 33805337279 |
| 18 | 161517974750 |
| 19 | 773643738505 |
| 20 | 3717199351855 |
| 21 | 17896679846060 |
| 22 | 86379015071009 |
| 23 | 417611710091614 |
| 24 | 2023077824973609 |
| 25 | 9814381630455424 |
| 26 | 47690808627818067 |
| 27 | 232019200929515380 |
[1,2,7,25,99,403,1719,7451,33116,148742,678430, 3117059,14468349,67515160,317323787,1497442597, 7103751478,33805337279,161517974750,773643738505, 3717199351855,17896679846060,86379015071009, 417611710091614,2023077824973609,9814381630455424, 47690808627818067,232019200929515380] |