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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 13 |
| 2 | 133 |
| 3 | 1225 |
| 4 | 10633 |
| 5 | 88837 |
| 6 | 722701 |
| 7 | 5764801 |
| 8 | 45294865 |
| 9 | 351652861 |
| 10 | 2703691669 |
| 11 | 20620693177 |
| 12 | 156208812697 |
| 13 | 1176509412085 |
| 14 | 8816899947037 |
| 15 | 65787638066353 |
| 16 | 488998835524129 |
| 17 | 3622389432086509 |
| 18 | 26752509108528805 |
| 19 | 197038045347164329 |
[1,13,133,1225,10633,88837,722701,5764801, 45294865,351652861,2703691669,20620693177, 156208812697,1176509412085,8816899947037, 65787638066353,488998835524129,3622389432086509, 26752509108528805,197038045347164329] |