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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 48 |
| 5 | 174 |
| 6 | 658 |
| 7 | 2482 |
| 8 | 9229 |
| 9 | 33982 |
| 10 | 125217 |
| 11 | 461351 |
| 12 | 1699127 |
| 13 | 6252129 |
| 14 | 22995280 |
| 15 | 84546207 |
| 16 | 310785413 |
| 17 | 1142206689 |
| 18 | 4197260747 |
| 19 | 15421867303 |
| 20 | 56659522539 |
| 21 | 208152496049 |
| 22 | 764662949438 |
| 23 | 2808941077111 |
| 24 | 10318186228202 |
[1,4,16,48,174,658,2482,9229,33982,125217,461351, 1699127,6252129,22995280,84546207,310785413, 1142206689,4197260747,15421867303,56659522539, 208152496049,764662949438,2808941077111, 10318186228202] |