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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 228 |
| 3 | 5040 |
| 4 | 121380 |
| 5 | 3093552 |
| 6 | 82047504 |
| 7 | 2240162496 |
| 8 | 62508328740 |
| 9 | 1773580002480 |
| 10 | 50988042273168 |
| 11 | 1481392081181376 |
| 12 | 43413834762798864 |
| 13 | 1281498837550545600 |
| 14 | 38059165854011995200 |
| 15 | 1136249610240102992640 |
| 16 | 34076899109906247654180 |
| 17 | 1026061759878805529676720 |
[1,12,228,5040,121380,3093552,82047504,2240162496, 62508328740,1773580002480,50988042273168, 1481392081181376,43413834762798864, 1281498837550545600,38059165854011995200, 1136249610240102992640,34076899109906247654180, 1026061759878805529676720] |