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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 25 |
| 4 | 78 |
| 5 | 238 |
| 6 | 721 |
| 7 | 2174 |
| 8 | 6540 |
| 9 | 19649 |
| 10 | 58994 |
| 11 | 177058 |
| 12 | 531297 |
| 13 | 1594090 |
| 14 | 4782592 |
| 15 | 14348297 |
| 16 | 43045734 |
| 17 | 129138566 |
| 18 | 387417905 |
| 19 | 1162257286 |
| 20 | 3486777636 |
| 21 | 10460342257 |
| 22 | 31381041898 |
| 23 | 94143150170 |
| 24 | 282429490113 |
| 25 | 847288534418 |
| 26 | 2541865706936 |
| 27 | 7625597288569 |
[1,2,8,25,78,238,721,2174,6540,19649,58994,177058, 531297,1594090,4782592,14348297,43045734, 129138566,387417905,1162257286,3486777636, 10460342257,31381041898,94143150170,282429490113, 847288534418,2541865706936,7625597288569] |