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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 66 |
| 4 | 4258 |
| 5 | 1337374 |
| 6 | 1933082159 |
| 7 | 11353941470188 |
| 8 | 291885138650054688 |
| 9 | 29463501750534915665304 |
| 10 | 12844314786465829040693498639 |
| 11 | 21675661852919288704454219459892060 |
| 12 | 156969579902607123047763327413679853875703 |
[1,2,6,66,4258,1337374,1933082159,11353941470188, 291885138650054688,29463501750534915665304, 12844314786465829040693498639, 21675661852919288704454219459892060, 156969579902607123047763327413679853875703] |