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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 0 |
| 4 | 161 |
| 5 | 5938 |
| 6 | 255029 |
| 7 | 112275165 |
| 8 | 141892377970 |
| 9 | 300456210546842 |
[0,4,0,161,5938,255029,112275165,141892377970, 300456210546842] |