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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 17 |
| 8 | 33 |
| 9 | 85 |
| 10 | 255 |
| 11 | 1137 |
| 12 | 4265 |
| 13 | 27311 |
| 14 | 122911 |
| 15 | 972783 |
| 16 | 6003645 |
| 17 | 62308027 |
| 18 | 499428829 |
| 19 | 6712583897 |
| 20 | 70003989585 |
| 21 | 1225387976695 |
| 22 | 16725199996985 |
[1,1,1,1,1,3,17,33,85,255,1137,4265,27311,122911, 972783,6003645,62308027,499428829,6712583897, 70003989585,1225387976695,16725199996985] |