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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 45 |
| 2 | 1350 |
| 3 | 34650 |
| 4 | 831600 |
| 5 | 19459440 |
| 6 | 454053600 |
| 7 | 10702692000 |
| 8 | 256864608000 |
| 9 | 6307453152000 |
| 10 | 158947819430400 |
| 11 | 4118193503424000 |
| 12 | 109818493424640000 |
| 13 | 3015784780968960000 |
| 14 | 85303626661693440000 |
[1,45,1350,34650,831600,19459440,454053600, 10702692000,256864608000,6307453152000, 158947819430400,4118193503424000, 109818493424640000,3015784780968960000, 85303626661693440000] |