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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 21 |
| 6 | 166 |
| 7 | 1247 |
| 8 | 7855 |
| 9 | 47245 |
| 10 | 284968 |
| 11 | 1741235 |
| 12 | 10782872 |
| 13 | 69537976 |
| 14 | 471717130 |
| 15 | 3336898255 |
| 16 | 24584784957 |
| 17 | 189704257763 |
| 18 | 1530649634720 |
| 19 | 12849873769593 |
| 20 | 111945035887787 |
| 21 | 1011184665775833 |
| 22 | 9458811859041042 |
| 23 | 91480934118104305 |
| 24 | 913112230809837136 |
| 25 | 9391472034599656856 |
[1,21,166,1247,7855,47245,284968,1741235,10782872, 69537976,471717130,3336898255,24584784957, 189704257763,1530649634720,12849873769593, 111945035887787,1011184665775833,9458811859041042, 91480934118104305,913112230809837136, 9391472034599656856] |