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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 32 |
| 4 | 190 |
| 5 | 1236 |
| 6 | 8482 |
| 7 | 60434 |
| 8 | 442788 |
| 9 | 3315046 |
| 10 | 25249888 |
| 11 | 195040914 |
| 12 | 1524256336 |
| 13 | 12030033178 |
| 14 | 95748941322 |
| 15 | 767655502862 |
| 16 | 6193902044684 |
| 17 | 50257335231264 |
| 18 | 409825115116030 |
| 19 | 3356850545246400 |
| 20 | 27606085924603602 |
| 21 | 227850606781308660 |
| 22 | 1886792409865105988 |
[1,2,6,32,190,1236,8482,60434,442788,3315046, 25249888,195040914,1524256336,12030033178, 95748941322,767655502862,6193902044684, 50257335231264,409825115116030,3356850545246400, 27606085924603602,227850606781308660, 1886792409865105988] |