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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 33 |
| 5 | 260 |
| 6 | 2648 |
| 7 | 26105 |
| 8 | 267195 |
| 9 | 2755322 |
| 10 | 28744852 |
| 11 | 302092789 |
| 12 | 3196248508 |
| 13 | 34007055286 |
[0,1,2,33,260,2648,26105,267195,2755322,28744852, 302092789,3196248508,34007055286] |