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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 11 |
| 3 | 91 |
| 4 | 671 |
| 5 | 4651 |
| 6 | 31031 |
| 7 | 201811 |
| 8 | 1288991 |
| 9 | 8124571 |
| 10 | 50700551 |
[0,1,11,91,671,4651,31031,201811,1288991,8124571, 50700551] |