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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 4 |
| 5 | 20 |
| 6 | 394 |
| 7 | 7538 |
| 8 | 501126 |
| 9 | 43679228 |
| 10 | 8515657512 |
| 11 | 2784504147786 |
[0,1,0,4,20,394,7538,501126,43679228,8515657512, 2784504147786] |