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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 13 |
| 6 | 43 |
| 7 | 905 |
| 8 | 15790 |
| 9 | 92494147 |
| 10 | 47283340087 |
| 11 | 8845558976879378539 |
| 12 | 2707131569835749037213946965347 |
| 13 | 2980435288285565929467276114849756995199455683357 |
[1,1,2,4,13,43,905,15790,92494147,47283340087, 8845558976879378539, 2707131569835749037213946965347, 2980435288285565929467276114849756995199455683357] |