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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 88 |
| 5 | 1496 |
| 6 | 34256 |
| 7 | 1305872 |
| 8 | 57804160 |
| 9 | 3960382848 |
| 10 | 288097804032 |
| 11 | 31177032137472 |
| 12 | 3374496463248384 |
| 13 | 530644850402565120 |
| 14 | 79955455534325999616 |
| 15 | 17241179374803330287616 |
| 16 | 3448609425518084068048896 |
| 17 | 977269122457749276877750272 |
| 18 | 250420488297020919542581493760 |
[1,1,2,10,88,1496,34256,1305872,57804160, 3960382848,288097804032,31177032137472, 3374496463248384,530644850402565120, 79955455534325999616,17241179374803330287616, 3448609425518084068048896, 977269122457749276877750272, 250420488297020919542581493760] |