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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 180 |
| 4 | 1680 |
| 5 | 12600 |
| 6 | 166320 |
| 7 | 2522520 |
| 8 | 576576 |
| 9 | 22054032 |
| 10 | 465585120 |
| 11 | 2560718160 |
| 12 | 64250746560 |
| 13 | 348024877200 |
| 14 | 1124388064800 |
| 15 | 4990906206000 |
| 16 | 165032631878400 |
| 17 | 350694342741600 |
| 18 | 2599263952084800 |
| 19 | 101515697684200800 |
[1,12,180,1680,12600,166320,2522520,576576, 22054032,465585120,2560718160,64250746560, 348024877200,1124388064800,4990906206000, 165032631878400,350694342741600,2599263952084800, 101515697684200800] |