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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 200 |
| 4 | 9996 |
| 5 | 499600 |
| 6 | 24970004 |
| 7 | 1248000600 |
| 8 | 62375059996 |
| 9 | 3117504999200 |
| 10 | 155812874900004 |
| 11 | 7787526240001000 |
| 12 | 389220499125149996 |
| 13 | 19453237430017498800 |
| 14 | 972272651001749790004 |
| 15 | 48594179312657472001400 |
[0,4,200,9996,499600,24970004,1248000600, 62375059996,3117504999200,155812874900004, 7787526240001000,389220499125149996, 19453237430017498800,972272651001749790004, 48594179312657472001400] |