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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 11 |
| 3 | 47 |
| 4 | 223 |
| 5 | 1135 |
| 6 | 6063 |
| 7 | 33535 |
| 8 | 190399 |
| 9 | 1103231 |
| 10 | 6497407 |
| 11 | 38779647 |
| 12 | 234043647 |
| 13 | 1425869567 |
| 14 | 8757326591 |
| 15 | 54163521535 |
| 16 | 337060285439 |
| 17 | 2108928587775 |
| 18 | 13258969458687 |
| 19 | 83720567447551 |
| 20 | 530692157964287 |
| 21 | 3375836610256895 |
[1,3,11,47,223,1135,6063,33535,190399,1103231, 6497407,38779647,234043647,1425869567,8757326591, 54163521535,337060285439,2108928587775, 13258969458687,83720567447551,530692157964287, 3375836610256895] |