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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 24 |
| 3 | 72 |
| 4 | 144 |
| 5 | 1584 |
| 6 | 32544 |
| 7 | 30528 |
| 8 | 188928 |
| 9 | 4030848 |
| 10 | 12029184 |
| 11 | 66104064 |
| 12 | 524719872 |
| 13 | 2364433920 |
| 14 | 28794737664 |
| 15 | 194617138176 |
| 16 | 962354727936 |
| 17 | 6901447938048 |
| 18 | 112061234884608 |
| 19 | 366020989931520 |
| 20 | 2592919032274944 |
| 21 | 19913392024584192 |
[2,24,72,144,1584,32544,30528,188928,4030848, 12029184,66104064,524719872,2364433920, 28794737664,194617138176,962354727936, 6901447938048,112061234884608,366020989931520, 2592919032274944,19913392024584192] |