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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 120 |
| 5 | 1810 |
| 6 | 37800 |
| 7 | 1036154 |
| 8 | 35906304 |
| 9 | 1529029674 |
| 10 | 78259648920 |
| 11 | 4729511693962 |
| 12 | 332593831890144 |
| 13 | 26886410844369674 |
| 14 | 2472715167660949848 |
| 15 | 256431103539829234410 |
| 16 | 29755101352498831197696 |
| 17 | 3837048614372255780199658 |
| 18 | 546600045766108847708692440 |
| 19 | 85556735070332670228234922442 |
[1,2,12,120,1810,37800,1036154,35906304, 1529029674,78259648920,4729511693962, 332593831890144,26886410844369674, 2472715167660949848,256431103539829234410, 29755101352498831197696,3837048614372255780199658, 546600045766108847708692440, 85556735070332670228234922442] |