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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 35 |
| 3 | 105 |
| 4 | 1155 |
| 5 | 15015 |
| 6 | 15015 |
| 7 | 255255 |
| 8 | 4849845 |
| 9 | 4849845 |
| 10 | 111546435 |
| 11 | 557732175 |
| 12 | 1673196525 |
| 13 | 48522699225 |
| 14 | 1504203675975 |
| 15 | 1504203675975 |
| 16 | 1504203675975 |
| 17 | 55655536011075 |
| 18 | 55655536011075 |
| 19 | 2281876976454075 |
| 20 | 98120709987525225 |
[1,5,35,105,1155,15015,15015,255255,4849845, 4849845,111546435,557732175,1673196525, 48522699225,1504203675975,1504203675975, 1504203675975,55655536011075,55655536011075, 2281876976454075,98120709987525225] |