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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 4 |
| 3 | 22 |
| 4 | 52 |
| 5 | 1522 |
| 6 | 29242 |
| 7 | 299512 |
| 8 | 4383592 |
| 9 | 188677702 |
| 10 | 5765999452 |
| 11 | 5765999452 |
| 12 | 2211931390882 |
| 13 | 165468170356702 |
| 14 | 8075975022064162 |
| 15 | 361310530977154972 |
| 16 | 20037783573808880092 |
| 17 | 1779852341342071295512 |
| 18 | 40235059344426324076912 |
| 19 | 4966347076439519105374252 |
| 20 | 169991099649125127278835142 |
[0,4,22,52,1522,29242,299512,4383592,188677702, 5765999452,5765999452,2211931390882, 165468170356702,8075975022064162, 361310530977154972,20037783573808880092, 1779852341342071295512,40235059344426324076912, 4966347076439519105374252, 169991099649125127278835142] |