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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 43 |
| 3 | 210 |
| 4 | 1162 |
| 5 | 6959 |
| 6 | 39608 |
| 7 | 226599 |
| 8 | 1305725 |
| 9 | 7497482 |
| 10 | 43051551 |
| 11 | 247361324 |
| 12 | 1420935204 |
| 13 | 8162170909 |
| 14 | 46887717710 |
| 15 | 269343435641 |
| 16 | 1547219822419 |
| 17 | 8887903925214 |
| 18 | 51055949141455 |
| 19 | 293287243303968 |
| 20 | 1684768052870030 |
[4,43,210,1162,6959,39608,226599,1305725,7497482, 43051551,247361324,1420935204,8162170909, 46887717710,269343435641,1547219822419, 8887903925214,51055949141455,293287243303968, 1684768052870030] |