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| n | a(n) |
|---|---|
| 1 | 480 |
| 2 | 123840 |
| 3 | 3150720 |
| 4 | 31704960 |
| 5 | 187502400 |
| 6 | 812885760 |
| 7 | 2767107840 |
| 8 | 8116473600 |
| 9 | 20671878240 |
| 10 | 48375619200 |
| 11 | 102892268160 |
| 12 | 208111357440 |
| 13 | 391550752320 |
| 14 | 713913822720 |
| 15 | 1230765753600 |
| 16 | 2077817249280 |
| 17 | 3348363579840 |
| 18 | 5333344585920 |
| 19 | 8152110268800 |
| 20 | 12384908524800 |
[480,123840,3150720,31704960,187502400,812885760, 2767107840,8116473600,20671878240,48375619200, 102892268160,208111357440,391550752320, 713913822720,1230765753600,2077817249280, 3348363579840,5333344585920,8152110268800, 12384908524800] |