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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 3 |
| 4 | 34 |
| 5 | 91 |
| 6 | 1430 |
| 7 | 12441 |
| 8 | 125970 |
| 9 | 3095547 |
| 10 | 67083870 |
| 11 | 1560337779 |
| 12 | 42483256530 |
| 13 | 1278362451795 |
| 14 | 50174604862382 |
| 15 | 3146934482482791 |
| 16 | 109416477603465890 |
| 17 | 4497598794363331965 |
| 18 | 327313882010942897070 |
| 19 | 14916466618879283766165 |
[1,0,3,34,91,1430,12441,125970,3095547,67083870, 1560337779,42483256530,1278362451795, 50174604862382,3146934482482791, 109416477603465890,4497598794363331965, 327313882010942897070,14916466618879283766165] |