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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 48 |
| 5 | 167 |
| 6 | 593 |
| 7 | 2144 |
| 8 | 7864 |
| 9 | 29171 |
| 10 | 109173 |
| 11 | 411501 |
| 12 | 1560089 |
| 13 | 5943199 |
| 14 | 22732739 |
| 15 | 87253604 |
| 16 | 335897864 |
| 17 | 1296447899 |
| 18 | 5015206349 |
| 19 | 19439895089 |
| 20 | 75487384829 |
| 21 | 293595204239 |
| 22 | 1143532045499 |
| 23 | 4459774977449 |
| 24 | 17413705988873 |
[1,4,14,48,167,593,2144,7864,29171,109173,411501, 1560089,5943199,22732739,87253604,335897864, 1296447899,5015206349,19439895089,75487384829, 293595204239,1143532045499,4459774977449, 17413705988873] |