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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 46 |
| 5 | 139 |
| 6 | 417 |
| 7 | 1250 |
| 8 | 3749 |
| 9 | 11247 |
| 10 | 33742 |
| 11 | 101227 |
| 12 | 303681 |
| 13 | 911042 |
| 14 | 2733125 |
| 15 | 8199375 |
| 16 | 24598126 |
| 17 | 73794379 |
| 18 | 221383137 |
| 19 | 664149410 |
| 20 | 1992448229 |
| 21 | 5977344687 |
| 22 | 17932034062 |
| 23 | 53796102187 |
| 24 | 161388306561 |
| 25 | 484164919682 |
| 26 | 1452494759045 |
[1,2,5,15,46,139,417,1250,3749,11247,33742,101227, 303681,911042,2733125,8199375,24598126,73794379, 221383137,664149410,1992448229,5977344687, 17932034062,53796102187,161388306561,484164919682, 1452494759045] |