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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 12 |
| 3 | 118 |
| 4 | 1634 |
| 5 | 29408 |
| 6 | 654040 |
| 7 | 17362056 |
| 8 | 536410200 |
| 9 | 18922946928 |
| 10 | 750902659200 |
| 11 | 33118793900784 |
| 12 | 1607673329621712 |
| 13 | 85192554602094912 |
| 14 | 4894219487974911552 |
| 15 | 303021216528999244416 |
| 16 | 20116223556200658052992 |
| 17 | 1425479651299747192856832 |
| 18 | 107400336067263661850548224 |
[1,2,12,118,1634,29408,654040,17362056,536410200, 18922946928,750902659200,33118793900784, 1607673329621712,85192554602094912, 4894219487974911552,303021216528999244416, 20116223556200658052992,1425479651299747192856832, 107400336067263661850548224] |