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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 366 |
| 3 | 13800 |
| 4 | 574650 |
| 5 | 25335072 |
| 6 | 1159174464 |
| 7 | 54435558672 |
| 8 | 2606102756730 |
| 9 | 126634810078920 |
| 10 | 6226427808402516 |
| 11 | 309095505195676992 |
| 12 | 15466884541698962736 |
| 13 | 779158533743408851200 |
| 14 | 39476348002042199114400 |
| 15 | 2010009672816216740255520 |
[1,12,366,13800,574650,25335072,1159174464, 54435558672,2606102756730,126634810078920, 6226427808402516,309095505195676992, 15466884541698962736,779158533743408851200, 39476348002042199114400,2010009672816216740255520] |