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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 35 |
| 5 | 110 |
| 6 | 1594 |
| 7 | 8064 |
| 8 | 125292 |
| 9 | 684144 |
| 10 | 14215536 |
| 11 | 102769920 |
| 12 | 2367099360 |
| 13 | 18380943360 |
| 14 | 463602216960 |
| 15 | 4776780072960 |
| 16 | 141702567955200 |
| 17 | 1382620380825600 |
| 18 | 46390044372940800 |
| 19 | 550153713457152000 |
| 20 | 19877486361997824000 |
| 21 | 261552662423506944000 |
| 22 | 9914502028911427584000 |
| 23 | 146055669195092557824000 |
[0,1,3,35,110,1594,8064,125292,684144,14215536, 102769920,2367099360,18380943360,463602216960, 4776780072960,141702567955200,1382620380825600, 46390044372940800,550153713457152000, 19877486361997824000,261552662423506944000, 9914502028911427584000,146055669195092557824000] |