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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 5 |
| 6 | 35 |
| 7 | 385 |
| 8 | 5005 |
| 9 | 85085 |
| 10 | 1956955 |
| 11 | 48923875 |
| 12 | 1516640125 |
| 13 | 53082404375 |
| 14 | 1964048961875 |
| 15 | 80526007436875 |
| 16 | 3784722349533125 |
| 17 | 200590284525255625 |
| 18 | 11032465648889059375 |
| 19 | 672980404582232621875 |
| 20 | 43743726297845120421875 |
[1,1,1,1,5,35,385,5005,85085,1956955,48923875, 1516640125,53082404375,1964048961875, 80526007436875,3784722349533125, 200590284525255625,11032465648889059375, 672980404582232621875,43743726297845120421875] |