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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 56 |
| 2 | 968 |
| 3 | 249728 |
| 4 | 3996680 |
| 5 | 1023152000 |
| 6 | 261926931584 |
| 7 | 17165643396644864 |
| 8 | 274650294346579976 |
| 9 | 70310475352724475776 |
| 10 | 17999481690297465818240 |
| 11 | 1179614032055334719872532480 |
| 12 | 301981192206165688287372558464 |
[2,56,968,249728,3996680,1023152000,261926931584, 17165643396644864,274650294346579976, 70310475352724475776,17999481690297465818240, 1179614032055334719872532480, 301981192206165688287372558464] |