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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 8 |
| 3 | 24 |
| 4 | 80 |
| 5 | 240 |
| 6 | 728 |
| 7 | 2184 |
| 8 | 6560 |
| 9 | 19680 |
| 10 | 59048 |
| 11 | 177144 |
| 12 | 531440 |
| 13 | 1594320 |
| 14 | 4782968 |
| 15 | 14348904 |
| 16 | 43046720 |
| 17 | 129140160 |
| 18 | 387420488 |
| 19 | 1162261464 |
| 20 | 3486784400 |
| 21 | 10460353200 |
| 22 | 31381059608 |
| 23 | 94143178824 |
| 24 | 282429536480 |
| 25 | 847288609440 |
[0,0,8,24,80,240,728,2184,6560,19680,59048,177144, 531440,1594320,4782968,14348904,43046720, 129140160,387420488,1162261464,3486784400, 10460353200,31381059608,94143178824,282429536480, 847288609440] |