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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 64 |
| 3 | 1152 |
| 4 | 12288 |
| 5 | 102400 |
| 6 | 737280 |
| 7 | 4816896 |
| 8 | 29360128 |
| 9 | 169869312 |
| 10 | 943718400 |
| 11 | 5075107840 |
| 12 | 26575110144 |
| 13 | 136096776192 |
| 14 | 683973541888 |
| 15 | 3382286745600 |
| 16 | 16492674416640 |
| 17 | 79439715106816 |
| 18 | 378506877861888 |
| 19 | 1786156639322112 |
[0,64,1152,12288,102400,737280,4816896,29360128, 169869312,943718400,5075107840,26575110144, 136096776192,683973541888,3382286745600, 16492674416640,79439715106816,378506877861888, 1786156639322112] |