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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 240 |
| 3 | 16934400 |
| 4 | 2433481408512000 |
| 5 | 1702585913798082900787200000 |
| 6 | 11371604489970305906683404111524659200000000 |
| 7 | 1255487625657168098911809977092685237691748290920448000000000000 |
[1,2,240,16934400,2433481408512000, 1702585913798082900787200000, 11371604489970305906683404111524659200000000, 12554876256571680989118099770926852376917482909204\ 48000000000000] |