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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 17 |
| 5 | 43 |
| 6 | 136 |
| 7 | 402 |
| 8 | 1180 |
| 9 | 3518 |
| 10 | 10525 |
| 11 | 31454 |
| 12 | 94059 |
| 13 | 281484 |
| 14 | 842574 |
| 15 | 2522415 |
| 16 | 7552239 |
| 17 | 22613578 |
| 18 | 67714627 |
| 19 | 202772197 |
| 20 | 607215863 |
| 21 | 1818375168 |
| 22 | 5445371326 |
| 23 | 16306993036 |
| 24 | 48833947510 |
| 25 | 146241553581 |
| 26 | 437945846008 |
| 27 | 1311506541151 |
[1,2,9,17,43,136,402,1180,3518,10525,31454,94059, 281484,842574,2522415,7552239,22613578,67714627, 202772197,607215863,1818375168,5445371326, 16306993036,48833947510,146241553581,437945846008, 1311506541151] |