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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 2 |
| 3 | 4 |
| 4 | 14 |
| 5 | 16 |
| 6 | 75 |
| 7 | 552 |
| 8 | 1667 |
| 9 | 11886 |
| 10 | 186036 |
| 11 | 1025514 |
| 12 | 13006464 |
| 13 | 369745208 |
| 14 | 3793772311 |
| 15 | 86085692189 |
[1,2,2,4,14,16,75,552,1667,11886,186036,1025514, 13006464,369745208,3793772311,86085692189] |