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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 32 |
| 5 | 184 |
| 6 | 1104 |
| 7 | 8448 |
| 8 | 67584 |
| 9 | 648576 |
| 10 | 6485760 |
| 11 | 74972160 |
| 12 | 899665920 |
| 13 | 12174658560 |
| 14 | 170445219840 |
| 15 | 2643856588800 |
| 16 | 42301705420800 |
| 17 | 740051782041600 |
| 18 | 13320932076748800 |
| 19 | 259500083163955200 |
| 20 | 5190001663279104000 |
| 21 | 111422936937037824000 |
| 22 | 2451304612614832128000 |
[0,1,2,8,32,184,1104,8448,67584,648576,6485760, 74972160,899665920,12174658560,170445219840, 2643856588800,42301705420800,740051782041600, 13320932076748800,259500083163955200, 5190001663279104000,111422936937037824000, 2451304612614832128000] |