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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 14 |
| 3 | 57 |
| 4 | 246 |
| 5 | 1038 |
| 6 | 4424 |
| 7 | 18777 |
| 8 | 79846 |
| 9 | 339258 |
| 10 | 1442004 |
| 11 | 6128202 |
| 12 | 26045436 |
| 13 | 110691948 |
| 14 | 470442924 |
| 15 | 1999378137 |
| 16 | 8497365126 |
| 17 | 36113785698 |
| 18 | 153483619604 |
| 19 | 652305322542 |
| 20 | 2772297736276 |
| 21 | 11782265148228 |
| 22 | 50074627320864 |
| 23 | 212817165231882 |
| 24 | 904472953925596 |
[1,3,14,57,246,1038,4424,18777,79846,339258, 1442004,6128202,26045436,110691948,470442924, 1999378137,8497365126,36113785698,153483619604, 652305322542,2772297736276,11782265148228, 50074627320864,212817165231882,904472953925596] |