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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 12 |
| 4 | 32 |
| 5 | 80 |
| 6 | 240 |
| 7 | 672 |
| 8 | 1792 |
| 9 | 5376 |
| 10 | 15360 |
| 11 | 42240 |
| 12 | 126720 |
| 13 | 366080 |
| 14 | 1025024 |
| 15 | 3075072 |
| 16 | 8945664 |
| 17 | 25346048 |
| 18 | 76038144 |
| 19 | 222265344 |
| 20 | 635043840 |
| 21 | 1905131520 |
| 22 | 5588385792 |
| 23 | 16066609152 |
| 24 | 48199827456 |
| 25 | 141764198400 |
| 26 | 409541017600 |
| 27 | 1228623052800 |
| 28 | 3621204787200 |
[1,2,4,12,32,80,240,672,1792,5376,15360,42240, 126720,366080,1025024,3075072,8945664,25346048, 76038144,222265344,635043840,1905131520, 5588385792,16066609152,48199827456,141764198400, 409541017600,1228623052800,3621204787200] |