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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 15 |
| 3 | 140 |
| 4 | 2520 |
| 5 | 88704 |
| 6 | 6150144 |
| 7 | 843448320 |
| 8 | 229417943040 |
| 9 | 123987652771840 |
| 10 | 133311524260282368 |
| 11 | 285432092670742757376 |
| 12 | 1217843595395169098137600 |
| 13 | 10360289146303272377017958400 |
| 14 | 175805226564926843718814452940800 |
[1,3,15,140,2520,88704,6150144,843448320, 229417943040,123987652771840,133311524260282368, 285432092670742757376,1217843595395169098137600, 10360289146303272377017958400, 175805226564926843718814452940800] |