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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 21 |
| 7 | 1640 |
| 8 | 407889 |
| 9 | 76204819 |
| 10 | 26261341398 |
| 11 | 12631545191076 |
[0,0,0,0,0,21,1640,407889,76204819,26261341398, 12631545191076] |