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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 26 |
| 3 | 168 |
| 4 | 736 |
| 5 | 2948 |
| 6 | 11434 |
| 7 | 42494 |
| 8 | 154886 |
| 9 | 554894 |
| 10 | 1962216 |
| 11 | 6863344 |
| 12 | 23793932 |
| 13 | 81876322 |
| 14 | 279975202 |
| 15 | 952219158 |
| 16 | 3223476464 |
| 17 | 10867630142 |
| 18 | 36506995228 |
| 19 | 122242241376 |
| 20 | 408146874402 |
| 21 | 1359207500258 |
| 22 | 4515810568242 |
| 23 | 14971262615738 |
[0,26,168,736,2948,11434,42494,154886,554894, 1962216,6863344,23793932,81876322,279975202, 952219158,3223476464,10867630142,36506995228, 122242241376,408146874402,1359207500258, 4515810568242,14971262615738] |