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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 52 |
| 4 | 35170 |
| 5 | 3535192 |
| 6 | 286234664 |
| 7 | 22890686508 |
| 8 | 1826093367100 |
| 9 | 144759756844954 |
[0,0,52,35170,3535192,286234664,22890686508, 1826093367100,144759756844954] |