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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 10 |
| 3 | 58 |
| 4 | 338 |
| 5 | 1970 |
| 6 | 11482 |
| 7 | 66922 |
| 8 | 390050 |
| 9 | 2273378 |
| 10 | 13250218 |
| 11 | 77227930 |
| 12 | 450117362 |
| 13 | 2623476242 |
| 14 | 15290740090 |
| 15 | 89120964298 |
| 16 | 519435045698 |
| 17 | 3027489309890 |
| 18 | 17645500813642 |
| 19 | 102845515571962 |
| 20 | 599427592618130 |
| 21 | 3493720040136818 |
| 22 | 20362892648202778 |
| 23 | 118683635849079850 |
[2,10,58,338,1970,11482,66922,390050,2273378, 13250218,77227930,450117362,2623476242, 15290740090,89120964298,519435045698, 3027489309890,17645500813642,102845515571962, 599427592618130,3493720040136818, 20362892648202778,118683635849079850] |