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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 96 |
| 4 | 1352 |
| 5 | 25400 |
| 6 | 597816 |
| 7 | 16941568 |
| 8 | 561993344 |
| 9 | 21372060672 |
| 10 | 916910785920 |
| 11 | 43817650647936 |
| 12 | 2308500130055808 |
| 13 | 132941831957885184 |
| 14 | 8308594453077321984 |
| 15 | 560108109905112238080 |
| 16 | 40514005700203717945344 |
| 17 | 3129925644058623770173440 |
[1,2,10,96,1352,25400,597816,16941568,561993344, 21372060672,916910785920,43817650647936, 2308500130055808,132941831957885184, 8308594453077321984,560108109905112238080, 40514005700203717945344,3129925644058623770173440] |