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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 20 |
| 4 | 154 |
| 5 | 1203 |
| 6 | 9824 |
| 7 | 83077 |
| 8 | 720110 |
| 9 | 6356062 |
| 10 | 56883199 |
| 11 | 514753678 |
| 12 | 4700984929 |
| 13 | 43258197713 |
[0,3,20,154,1203,9824,83077,720110,6356062, 56883199,514753678,4700984929,43258197713] |