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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 31 |
| 3 | 225 |
| 4 | 1563 |
| 5 | 10222 |
| 6 | 63030 |
| 7 | 374264 |
| 8 | 2160300 |
| 9 | 12196405 |
| 10 | 67724342 |
| 11 | 371233523 |
| 12 | 2014305995 |
[0,31,225,1563,10222,63030,374264,2160300, 12196405,67724342,371233523,2014305995] |