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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 49 |
| 6 | 268 |
| 7 | 1505 |
| 8 | 9667 |
| 9 | 81891 |
| 10 | 779193 |
| 11 | 7726623 |
| 12 | 80770479 |
| 13 | 921442854 |
| 14 | 11621384700 |
| 15 | 159894957124 |
[1,1,2,10,49,268,1505,9667,81891,779193,7726623, 80770479,921442854,11621384700,159894957124] |