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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 196 |
| 3 | 3120 |
| 4 | 50020 |
| 5 | 799536 |
| 6 | 12799632 |
| 7 | 204724416 |
| 8 | 3276326820 |
| 9 | 52413049520 |
| 10 | 838703348496 |
| 11 | 13418125153472 |
| 12 | 214703825630736 |
| 13 | 3435088134123200 |
| 14 | 54963617747611200 |
| 15 | 879389273444524800 |
| 16 | 14070604335190692900 |
| 17 | 225124668703739770800 |
| 18 | 3602061930346132909200 |
[1,12,196,3120,50020,799536,12799632,204724416, 3276326820,52413049520,838703348496, 13418125153472,214703825630736,3435088134123200, 54963617747611200,879389273444524800, 14070604335190692900,225124668703739770800, 3602061930346132909200] |