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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 15 |
| 4 | 124 |
| 5 | 1605 |
| 6 | 23826 |
| 7 | 446131 |
| 8 | 9494696 |
| 9 | 234924633 |
| 10 | 6489737830 |
| 11 | 200530623711 |
| 12 | 6804957067404 |
| 13 | 252717429733093 |
| 14 | 10170665548897322 |
| 15 | 441656425701309435 |
| 16 | 20567515843800970576 |
| 17 | 1023126772183618699185 |
| 18 | 54132939273244418609742 |
| 19 | 3036227079039027495953815 |
[0,1,2,15,124,1605,23826,446131,9494696,234924633, 6489737830,200530623711,6804957067404, 252717429733093,10170665548897322, 441656425701309435,20567515843800970576, 1023126772183618699185,54132939273244418609742, 3036227079039027495953815] |