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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 13 |
| 4 | 42 |
| 5 | 138 |
| 6 | 482 |
| 7 | 1674 |
| 8 | 6193 |
| 9 | 22905 |
| 10 | 87302 |
| 11 | 332124 |
| 12 | 1300396 |
| 13 | 5086323 |
| 14 | 20241313 |
| 15 | 80532296 |
| 16 | 325512139 |
| 17 | 1315265248 |
| 18 | 5373186309 |
| 19 | 21959388097 |
| 20 | 90618415683 |
| 21 | 374030443628 |
| 22 | 1555349602195 |
| 23 | 6471926603762 |
| 24 | 27103293936363 |
| 25 | 113566464857234 |
| 26 | 478365524549750 |
| 27 | 2016520963230236 |
| 28 | 8538774214340379 |
[1,2,5,13,42,138,482,1674,6193,22905,87302,332124, 1300396,5086323,20241313,80532296,325512139, 1315265248,5373186309,21959388097,90618415683, 374030443628,1555349602195,6471926603762, 27103293936363,113566464857234,478365524549750, 2016520963230236,8538774214340379] |