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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 3 |
| 4 | 52 |
| 5 | 245 |
| 6 | 4206 |
| 7 | 37807 |
| 8 | 712552 |
| 9 | 9755433 |
| 10 | 207915490 |
| 11 | 3830073731 |
| 12 | 92948571420 |
| 13 | 2139142283005 |
| 14 | 58945940093782 |
| 15 | 1617324856023255 |
| 16 | 50252559901690576 |
| 17 | 1593701025177559121 |
| 18 | 55366628370374688714 |
| 19 | 1986560560083994301611 |
[1,0,2,3,52,245,4206,37807,712552,9755433, 207915490,3830073731,92948571420,2139142283005, 58945940093782,1617324856023255,50252559901690576, 1593701025177559121,55366628370374688714, 1986560560083994301611] |