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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 52 |
| 4 | 2150 |
| 5 | 423804 |
| 6 | 358766428 |
| 7 | 1257303170984 |
| 8 | 18016913850523398 |
| 9 | 1049450810327077624300 |
| 10 | 247590106794776589832254260 |
| 11 | 236013988752078034604114551553880 |
| 12 | 907420117150975291421488593816623266780 |
| 13 | 14052902173791695936955751957273562543384799320 |
[1,2,6,52,2150,423804,358766428,1257303170984, 18016913850523398,1049450810327077624300, 247590106794776589832254260, 236013988752078034604114551553880, 907420117150975291421488593816623266780, 14052902173791695936955751957273562543384799320] |