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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 36 |
| 5 | 216 |
| 6 | 1440 |
| 7 | 11520 |
| 8 | 103824 |
| 9 | 1032192 |
| 10 | 11311488 |
| 11 | 135432000 |
| 12 | 1756751040 |
| 13 | 24546246912 |
| 14 | 367583014656 |
| 15 | 5872797874944 |
| 16 | 99709066195200 |
| 17 | 1792707696046080 |
| 18 | 34026520304848896 |
| 19 | 679901687704470528 |
| 20 | 14265989230889290752 |
| 21 | 313612842057647616000 |
| 22 | 7208078043054064619520 |
| 23 | 172883491724308733964288 |
| 24 | 4319548522560325245210624 |
[0,1,2,6,36,216,1440,11520,103824,1032192, 11311488,135432000,1756751040,24546246912, 367583014656,5872797874944,99709066195200, 1792707696046080,34026520304848896, 679901687704470528,14265989230889290752, 313612842057647616000,7208078043054064619520, 172883491724308733964288, 4319548522560325245210624] |