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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 7800 |
| 4 | 0 |
| 5 | 2787453552000000 |
| 6 | 0 |
| 7 | 3108366378804858902744832000000000000 |
| 8 | 0 |
| 9 | 165290679439545659068950724771043004678057040281600000000000000000000 |
| 10 | 0 |
[1,0,7800,0,2787453552000000,0, 3108366378804858902744832000000000000,0, 16529067943954565906895072477104300467805704028160\ 0000000000000000000,0] |