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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 6912 |
| 4 | 1632586752 |
| 5 | 92771293593600000 |
| 6 | 1922167968750000000000000000 |
| 7 | 20386493620375898676722605059420979200000 |
| 8 | 147691962494584259939724821292542617401603191419699200000 |
[0,4,6912,1632586752,92771293593600000, 1922167968750000000000000000, 20386493620375898676722605059420979200000, 14769196249458425993972482129254261740160319141969\ 9200000] |