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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 36 |
| 6 | 234 |
| 7 | 1597 |
| 8 | 12459 |
| 9 | 111451 |
| 10 | 1116277 |
| 11 | 12298958 |
| 12 | 147655760 |
| 13 | 1919465237 |
| 14 | 26870436345 |
| 15 | 403044639709 |
| 16 | 6448695657957 |
| 17 | 109628096021612 |
| 18 | 1973308547820586 |
| 19 | 37492874766408001 |
| 20 | 749857477972731979 |
| 21 | 15747006284752049759 |
| 22 | 346434131946498886045 |
[0,1,1,1,5,36,234,1597,12459,111451,1116277, 12298958,147655760,1919465237,26870436345, 403044639709,6448695657957,109628096021612, 1973308547820586,37492874766408001, 749857477972731979,15747006284752049759, 346434131946498886045] |