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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 37 |
| 4 | 307 |
| 5 | 2858 |
| 6 | 32060 |
| 7 | 405830 |
| 8 | 5777354 |
| 9 | 91400200 |
| 10 | 1593023040 |
| 11 | 30251766840 |
| 12 | 622016655816 |
| 13 | 13777150847952 |
| 14 | 327040289212320 |
| 15 | 8280040187137200 |
| 16 | 222696435041359824 |
| 17 | 6341359225470493440 |
| 18 | 190609840724078576256 |
| 19 | 6031297367477133540480 |
| 20 | 200389374367707186619776 |
[1,6,37,307,2858,32060,405830,5777354,91400200, 1593023040,30251766840,622016655816, 13777150847952,327040289212320,8280040187137200, 222696435041359824,6341359225470493440, 190609840724078576256,6031297367477133540480, 200389374367707186619776] |