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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 9 |
| 3 | 22 |
| 4 | 57 |
| 5 | 150 |
| 6 | 444 |
| 7 | 1362 |
| 8 | 4497 |
| 9 | 15338 |
| 10 | 54018 |
| 11 | 193722 |
| 12 | 705392 |
| 13 | 2593398 |
| 14 | 9612144 |
| 15 | 35840622 |
| 16 | 134318097 |
| 17 | 505486878 |
| 18 | 1909275084 |
| 19 | 7234415562 |
| 20 | 27489389850 |
| 21 | 104718539638 |
| 22 | 399828796884 |
| 23 | 1529767891122 |
| 24 | 5864087533072 |
| 25 | 22518048468582 |
| 26 | 86607787095594 |
| 27 | 333600173734122 |
[3,9,22,57,150,444,1362,4497,15338,54018,193722, 705392,2593398,9612144,35840622,134318097, 505486878,1909275084,7234415562,27489389850, 104718539638,399828796884,1529767891122, 5864087533072,22518048468582,86607787095594, 333600173734122] |