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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 25 |
| 4 | 210 |
| 5 | 1755 |
| 6 | 17339 |
| 7 | 177097 |
| 8 | 1888153 |
| 9 | 20587627 |
| 10 | 228891069 |
| 11 | 2582512649 |
| 12 | 29499246456 |
[1,7,25,210,1755,17339,177097,1888153,20587627, 228891069,2582512649,29499246456] |