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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 25 |
| 6 | 216 |
| 7 | 963 |
| 8 | 23435 |
| 9 | 92225 |
| 10 | 2729205 |
| 11 | 17313348 |
| 12 | 182553725 |
| 13 | 4235194171 |
[1,1,3,7,25,216,963,23435,92225,2729205,17313348, 182553725,4235194171] |