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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 166 |
| 5 | 1185 |
| 6 | 26577 |
| 7 | 342596 |
| 8 | 9804507 |
| 9 | 220905716 |
| 10 | 9470663034 |
| 11 | 400580293516 |
[1,4,11,166,1185,26577,342596,9804507,220905716, 9470663034,400580293516] |