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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 320 |
| 3 | 10935 |
| 4 | 139264 |
| 5 | 1015625 |
| 6 | 5178816 |
| 7 | 20588575 |
| 8 | 68157440 |
| 9 | 196101729 |
| 10 | 505000000 |
| 11 | 1188717431 |
| 12 | 2597806080 |
| 13 | 5333623945 |
| 14 | 10383230144 |
| 15 | 19307109375 |
| 16 | 34493956096 |
| 17 | 59499107585 |
| 18 | 99485755200 |
| 19 | 161790784759 |
| 20 | 256640000000 |
| 21 | 398040567561 |
| 22 | 604881787840 |
| 23 | 902278743455 |
[0,1,320,10935,139264,1015625,5178816,20588575, 68157440,196101729,505000000,1188717431, 2597806080,5333623945,10383230144,19307109375, 34493956096,59499107585,99485755200,161790784759, 256640000000,398040567561,604881787840, 902278743455] |