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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 20 |
| 4 | 153 |
| 5 | 1198 |
| 6 | 9805 |
| 7 | 83022 |
| 8 | 720033 |
| 9 | 6356346 |
| 10 | 56881516 |
| 11 | 514760166 |
| 12 | 4700997055 |
| 13 | 43258200645 |
[0,3,20,153,1198,9805,83022,720033,6356346, 56881516,514760166,4700997055,43258200645] |