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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 17 |
| 5 | 82 |
| 6 | 489 |
| 7 | 2923 |
| 8 | 18401 |
| 9 | 116848 |
| 10 | 753726 |
| 11 | 4898579 |
| 12 | 32085696 |
| 13 | 211398614 |
| 14 | 1400292492 |
| 15 | 9318028028 |
| 16 | 62259251309 |
| 17 | 417496576187 |
[0,1,3,17,82,489,2923,18401,116848,753726,4898579, 32085696,211398614,1400292492,9318028028, 62259251309,417496576187] |