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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 80 |
| 5 | 876 |
| 6 | 12192 |
| 7 | 206144 |
| 8 | 4104704 |
| 9 | 94092112 |
| 10 | 2440642560 |
| 11 | 70676191840 |
| 12 | 2260198354944 |
| 13 | 79113937385536 |
| 14 | 3008546200346624 |
| 15 | 123513154739070976 |
| 16 | 5444598073252904960 |
| 17 | 256489070938397360384 |
| 18 | 12859678961654923395072 |
| 19 | 683701585124386481758720 |
[1,2,10,80,876,12192,206144,4104704,94092112, 2440642560,70676191840,2260198354944, 79113937385536,3008546200346624, 123513154739070976,5444598073252904960, 256489070938397360384,12859678961654923395072, 683701585124386481758720] |