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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 140 |
| 4 | 10296 |
| 5 | 1560090 |
| 6 | 818269800 |
| 7 | 890504276970 |
| 8 | 578105086816530 |
| 9 | 845098382127164340 |
| 10 | 1345577210752717337010 |
| 11 | 2349420395175736366400280 |
| 12 | 4072812804055080385050520770 |
| 13 | 16954222832305267550769863845710 |
[1,6,140,10296,1560090,818269800,890504276970, 578105086816530,845098382127164340, 1345577210752717337010,2349420395175736366400280, 4072812804055080385050520770, 16954222832305267550769863845710] |