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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 42 |
| 5 | 429 |
| 6 | 7436 |
| 7 | 218348 |
| 8 | 10850216 |
| 9 | 911835460 |
| 10 | 129534272700 |
| 11 | 31095744852375 |
| 12 | 12611311859677500 |
| 13 | 8639383518297652500 |
| 14 | 9995541355448167482000 |
| 15 | 19529076234661277104897200 |
| 16 | 64427185703425689356896743840 |
| 17 | 358869201916137601447486156417296 |
[1,1,2,7,42,429,7436,218348,10850216,911835460, 129534272700,31095744852375,12611311859677500, 8639383518297652500,9995541355448167482000, 19529076234661277104897200, 64427185703425689356896743840, 358869201916137601447486156417296] |