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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 24 |
| 4 | 120 |
| 5 | 840 |
| 6 | 6720 |
| 7 | 60480 |
| 8 | 604800 |
| 9 | 6652800 |
| 10 | 79833600 |
| 11 | 1037836800 |
| 12 | 14529715200 |
| 13 | 217945728000 |
| 14 | 3487131648000 |
| 15 | 59281238016000 |
| 16 | 1067062284288000 |
| 17 | 20274183401472000 |
| 18 | 405483668029440000 |
| 19 | 8515157028618240000 |
| 20 | 187333454629601280000 |
| 21 | 4308669456480829440000 |
| 22 | 107716736412020736000000 |
[1,3,6,24,120,840,6720,60480,604800,6652800, 79833600,1037836800,14529715200,217945728000, 3487131648000,59281238016000,1067062284288000, 20274183401472000,405483668029440000, 8515157028618240000,187333454629601280000, 4308669456480829440000,107716736412020736000000] |