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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 8 |
| 4 | 64 |
| 5 | 540 |
| 6 | 4920 |
| 7 | 48720 |
| 8 | 524160 |
| 9 | 6108480 |
| 10 | 76809600 |
| 11 | 1037836800 |
| 12 | 15008716800 |
| 13 | 231437606400 |
| 14 | 3792255667200 |
| 15 | 65819609856000 |
| 16 | 1206547550208000 |
| 17 | 23297526540288000 |
| 18 | 472708591939584000 |
| 19 | 10055994967130112000 |
| 20 | 223826984752250880000 |
| 21 | 5202760944485744640000 |
| 22 | 126075414965721661440000 |
| 23 | 3179798058882852126720000 |
| 24 | 83346901966165164687360000 |
| 25 | 2267221868000212451328000000 |
[0,0,1,8,64,540,4920,48720,524160,6108480, 76809600,1037836800,15008716800,231437606400, 3792255667200,65819609856000,1206547550208000, 23297526540288000,472708591939584000, 10055994967130112000,223826984752250880000, 5202760944485744640000,126075414965721661440000, 3179798058882852126720000, 83346901966165164687360000, 2267221868000212451328000000] |