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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 12 |
| 4 | 24 |
| 5 | 72 |
| 6 | 360 |
| 7 | 2520 |
| 8 | 5040 |
| 9 | 55440 |
| 10 | 277200 |
| 11 | 3603600 |
| 12 | 10810800 |
| 13 | 21621600 |
| 14 | 367567200 |
| 15 | 6983776800 |
| 16 | 160626866400 |
| 17 | 1124388064800 |
| 18 | 32607253879200 |
| 19 | 1010824870255200 |
| 20 | 2021649740510400 |
| 21 | 74801040398884800 |
| 22 | 224403121196654400 |
[1,4,12,24,72,360,2520,5040,55440,277200,3603600, 10810800,21621600,367567200,6983776800, 160626866400,1124388064800,32607253879200, 1010824870255200,2021649740510400, 74801040398884800,224403121196654400] |