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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1200 |
| 2 | 202450 |
| 3 | 11389600 |
| 4 | 285385200 |
| 5 | 3779134240 |
| 6 | 30885301600 |
| 7 | 181284196800 |
| 8 | 842726826450 |
| 9 | 3262594952400 |
| 10 | 10968671291040 |
| 11 | 32802221530400 |
| 12 | 89267475949600 |
| 13 | 223991253535200 |
| 14 | 525491835433600 |
| 15 | 1161295395893440 |
| 16 | 2440508069871600 |
| 17 | 4898380398568000 |
| 18 | 9456583413620850 |
| 19 | 17601674014456800 |
[1,1200,202450,11389600,285385200,3779134240, 30885301600,181284196800,842726826450, 3262594952400,10968671291040,32802221530400, 89267475949600,223991253535200,525491835433600, 1161295395893440,2440508069871600, 4898380398568000,9456583413620850, 17601674014456800] |