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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 98 |
| 5 | 394 |
| 6 | 1627 |
| 7 | 6860 |
| 8 | 29349 |
| 9 | 126916 |
| 10 | 554542 |
| 11 | 2441671 |
| 12 | 10821253 |
| 13 | 48242580 |
| 14 | 216133921 |
| 15 | 972469535 |
| 16 | 4392665982 |
| 17 | 19909498340 |
| 18 | 90514195277 |
| 19 | 412656103177 |
| 20 | 1886035509909 |
| 21 | 8639801473299 |
| 22 | 39662054299905 |
| 23 | 182425279994149 |
| 24 | 840558556157834 |
| 25 | 3879455984619635 |
| 26 | 17932467022510137 |
| 27 | 83009868499660146 |
[1,2,7,25,98,394,1627,6860,29349,126916,554542, 2441671,10821253,48242580,216133921,972469535, 4392665982,19909498340,90514195277,412656103177, 1886035509909,8639801473299,39662054299905, 182425279994149,840558556157834,3879455984619635, 17932467022510137,83009868499660146] |