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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 77 |
| 4 | 1222 |
| 5 | 26364 |
| 6 | 739608 |
| 7 | 26079780 |
| 8 | 1125791280 |
| 9 | 58257484128 |
| 10 | 3552890064480 |
| 11 | 251777905728480 |
| 12 | 20488109614761600 |
| 13 | 1895120214639868800 |
| 14 | 197527783071095930880 |
| 15 | 23023412842885582176000 |
| 16 | 2980946191374310495795200 |
| 17 | 426192103002275699198054400 |
[0,1,7,77,1222,26364,739608,26079780,1125791280, 58257484128,3552890064480,251777905728480, 20488109614761600,1895120214639868800, 197527783071095930880,23023412842885582176000, 2980946191374310495795200, 426192103002275699198054400] |