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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 8 |
| 5 | 54 |
| 6 | 162 |
| 7 | 1536 |
| 8 | 6144 |
| 9 | 75000 |
| 10 | 375000 |
| 11 | 5598720 |
| 12 | 33592320 |
| 13 | 592950960 |
| 14 | 4150656720 |
| 15 | 84557168640 |
| 16 | 676457349120 |
| 17 | 15620794116480 |
| 18 | 140587147048320 |
| 19 | 3628800000000000 |
| 20 | 36288000000000000 |
| 21 | 1035338990313196800 |
| 22 | 11388728893445164800 |
| 23 | 355902198372945100800 |
[1,1,1,4,8,54,162,1536,6144,75000,375000,5598720, 33592320,592950960,4150656720,84557168640, 676457349120,15620794116480,140587147048320, 3628800000000000,36288000000000000, 1035338990313196800,11388728893445164800, 355902198372945100800] |