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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 15 |
| 2 | 223 |
| 3 | 49726 |
| 4 | 2472675072 |
| 5 | 6114122011690205179 |
| 6 | 37382487973834681475536573127118422035 |
| 7 | 1397450407113894589170760370457882734663916414838438245542265330668373541218 |
[4,15,223,49726,2472675072,6114122011690205179, 37382487973834681475536573127118422035, 13974504071138945891707603704578827346639164148384\ 38245542265330668373541218] |