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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 20 |
| 4 | 624 |
| 5 | 55248 |
| 6 | 13982208 |
| 7 | 10358360640 |
| 8 | 22792648882176 |
| 9 | 149888345786341632 |
| 10 | 2952810709943411146752 |
| 11 | 174416705255313941476193280 |
| 12 | 30901060796613886817249881227264 |
| 13 | 16422801513633911416125344647746244608 |
| 14 | 26183660776604240464418800095675915958222848 |
[1,2,20,624,55248,13982208,10358360640, 22792648882176,149888345786341632, 2952810709943411146752, 174416705255313941476193280, 30901060796613886817249881227264, 16422801513633911416125344647746244608, 26183660776604240464418800095675915958222848] |