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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 30 |
| 6 | 290 |
| 7 | 5795 |
| 8 | 273131 |
| 9 | 33435365 |
| 10 | 11684100029 |
| 11 | 12420429123560 |
| 12 | 42758167792063420 |
| 13 | 497197306541110815666 |
| 14 | 20499715659897938314285818 |
| 15 | 3096905029809572116833551189888 |
| 16 | 1787271136443917603307861222439598096 |
| 17 | 4049832282285832299658439630909210798514596 |
[1,1,1,2,6,30,290,5795,273131,33435365, 11684100029,12420429123560,42758167792063420, 497197306541110815666,20499715659897938314285818, 3096905029809572116833551189888, 1787271136443917603307861222439598096, 4049832282285832299658439630909210798514596] |