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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 6 |
| 5 | 60 |
| 6 | 300 |
| 7 | 1296 |
| 8 | 6048 |
| 9 | 30240 |
| 10 | 159408 |
| 11 | 883872 |
| 12 | 5018112 |
| 13 | 28304640 |
| 14 | 157697280 |
| 15 | 876311654 |
| 16 | 4895520768 |
| 17 | 27554100480 |
| 18 | 156139902720 |
| 19 | 889181991936 |
| 20 | 5078255822436 |
| 21 | 29046943180800 |
| 22 | 166354131141818 |
| 23 | 954240788994048 |
| 24 | 5484206701412352 |
| 25 | 31581437286776820 |
[0,0,0,6,60,300,1296,6048,30240,159408,883872, 5018112,28304640,157697280,876311654,4895520768, 27554100480,156139902720,889181991936, 5078255822436,29046943180800,166354131141818, 954240788994048,5484206701412352, 31581437286776820] |