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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 224 |
| 3 | 4096 |
| 4 | 31200 |
| 5 | 147456 |
| 6 | 522880 |
| 7 | 1548288 |
| 8 | 3977696 |
| 9 | 9011200 |
| 10 | 18679872 |
| 11 | 36679680 |
| 12 | 68003456 |
| 13 | 118112256 |
| 14 | 196860160 |
| 15 | 321773568 |
| 16 | 509276640 |
| 17 | 772374528 |
| 18 | 1143964768 |
| 19 | 1682657280 |
| 20 | 2428094016 |
| 21 | 3391815680 |
[1,0,224,4096,31200,147456,522880,1548288,3977696, 9011200,18679872,36679680,68003456,118112256, 196860160,321773568,509276640,772374528, 1143964768,1682657280,2428094016,3391815680] |