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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 8 |
| 5 | 24 |
| 6 | 144 |
| 7 | 720 |
| 8 | 5760 |
| 9 | 40320 |
| 10 | 403200 |
| 11 | 3628800 |
| 12 | 43545600 |
| 13 | 479001600 |
| 14 | 6706022400 |
| 15 | 87178291200 |
| 16 | 1394852659200 |
| 17 | 20922789888000 |
| 18 | 376610217984000 |
| 19 | 6402373705728000 |
| 20 | 128047474114560000 |
| 21 | 2432902008176640000 |
| 22 | 53523844179886080000 |
| 23 | 1124000727777607680000 |
[0,1,2,2,8,24,144,720,5760,40320,403200,3628800, 43545600,479001600,6706022400,87178291200, 1394852659200,20922789888000,376610217984000, 6402373705728000,128047474114560000, 2432902008176640000,53523844179886080000, 1124000727777607680000] |