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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 15 |
| 6 | 195 |
| 7 | 105 |
| 8 | 2625 |
| 9 | 945 |
| 10 | 38745 |
| 11 | 10395 |
| 12 | 634095 |
| 13 | 135135 |
| 14 | 11486475 |
| 15 | 2027025 |
| 16 | 229053825 |
| 17 | 34459425 |
| 18 | 4996616625 |
| 19 | 654729075 |
| 20 | 118505962575 |
| 21 | 13749310575 |
| 22 | 3038597637075 |
| 23 | 316234143225 |
| 24 | 83802047954625 |
| 25 | 7905853580625 |
| 26 | 2474532170735625 |
| 27 | 213458046676875 |
[1,3,15,15,195,105,2625,945,38745,10395,634095, 135135,11486475,2027025,229053825,34459425, 4996616625,654729075,118505962575,13749310575, 3038597637075,316234143225,83802047954625, 7905853580625,2474532170735625,213458046676875] |