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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 10 |
| 3 | 34 |
| 4 | 114 |
| 5 | 374 |
| 6 | 1222 |
| 7 | 3994 |
| 8 | 13058 |
| 9 | 42694 |
| 10 | 139590 |
| 11 | 456394 |
| 12 | 1492194 |
| 13 | 4878774 |
| 14 | 15951302 |
| 15 | 52153274 |
| 16 | 170516738 |
| 17 | 557509734 |
| 18 | 1822795270 |
| 19 | 5959685354 |
| 20 | 19485375074 |
| 21 | 63708034774 |
| 22 | 208295384582 |
| 23 | 681028184154 |
| 24 | 2226642652418 |
| 25 | 7280076826374 |
| 26 | 23802435716550 |
| 27 | 77822797691914 |
[4,10,34,114,374,1222,3994,13058,42694,139590, 456394,1492194,4878774,15951302,52153274, 170516738,557509734,1822795270,5959685354, 19485375074,63708034774,208295384582,681028184154, 2226642652418,7280076826374,23802435716550, 77822797691914] |