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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 72 |
| 3 | 32 |
| 4 | 14400 |
| 5 | 1728 |
| 6 | 2540160 |
| 7 | 138240 |
| 8 | 261273600 |
| 9 | 896000 |
| 10 | 10538035200 |
| 11 | 209018880 |
| 12 | 407994402816000 |
| 13 | 5633058816000 |
| 14 | 941525544960000 |
| 15 | 4723310592 |
| 16 | 8707228239790080000 |
| 17 | 6162712657920000 |
| 18 | 17473102222724628480000 |
| 19 | 107559878256230400000 |
| 20 | 14162409169997856768000000 |
[4,72,32,14400,1728,2540160,138240,261273600, 896000,10538035200,209018880,407994402816000, 5633058816000,941525544960000,4723310592, 8707228239790080000,6162712657920000, 17473102222724628480000,107559878256230400000, 14162409169997856768000000] |