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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 6 |
| 3 | 264 |
| 4 | 19764 |
| 5 | 2865780 |
| 6 | 890824020 |
| 7 | 613195191972 |
| 8 | 954838111013352 |
| 9 | 3403478388512845692 |
| 10 | 27993333042034653078324 |
| 11 | 534183142761328458054883788 |
| 12 | 23742792574386065523445979163924 |
[0,6,264,19764,2865780,890824020,613195191972, 954838111013352,3403478388512845692, 27993333042034653078324, 534183142761328458054883788, 23742792574386065523445979163924] |