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| n | a(n) |
|---|---|
| 1 | 12 |
| 2 | 120 |
| 3 | 840 |
| 4 | 5178 |
| 5 | 29772 |
| 6 | 163878 |
| 7 | 875592 |
| 8 | 4578186 |
| 9 | 23548164 |
| 10 | 119570574 |
| 11 | 600870336 |
| 12 | 2993807250 |
| 13 | 14810051580 |
| 14 | 72819229974 |
| 15 | 356173467576 |
| 16 | 1734202809114 |
| 17 | 8410141924596 |
| 18 | 40641730213278 |
| 19 | 195782548631472 |
| 20 | 940481337385122 |
[12,120,840,5178,29772,163878,875592,4578186, 23548164,119570574,600870336,2993807250, 14810051580,72819229974,356173467576, 1734202809114,8410141924596,40641730213278, 195782548631472,940481337385122] |