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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 84 |
| 2 | 27720 |
| 3 | 13693680 |
| 4 | 5354228880 |
| 5 | 2489716429200 |
| 6 | 1010824870255200 |
| 7 | 459492105307435200 |
| 8 | 189737418627305920800 |
| 9 | 85223723866764909426000 |
| 10 | 35532611270849849570013600 |
| 11 | 15842376246977818384652245440 |
| 12 | 6646596943618421076833646609600 |
| 13 | 2948532659526725719238433845966400 |
[1,84,27720,13693680,5354228880,2489716429200, 1010824870255200,459492105307435200, 189737418627305920800,85223723866764909426000, 35532611270849849570013600, 15842376246977818384652245440, 6646596943618421076833646609600, 2948532659526725719238433845966400] |