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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 6 |
| 2 | 19 |
| 3 | 61 |
| 4 | 196 |
| 5 | 630 |
| 6 | 2026 |
| 7 | 6516 |
| 8 | 20957 |
| 9 | 67403 |
| 10 | 216786 |
| 11 | 697242 |
| 12 | 2242518 |
| 13 | 7212542 |
| 14 | 23197479 |
| 15 | 74609345 |
| 16 | 239963764 |
| 17 | 771788146 |
| 18 | 2482278710 |
| 19 | 7983677420 |
| 20 | 25677658553 |
| 21 | 82586271223 |
| 22 | 265619709074 |
| 23 | 854304581182 |
| 24 | 2747673807690 |
| 25 | 8837259590742 |
| 26 | 28423008894139 |
[2,6,19,61,196,630,2026,6516,20957,67403,216786, 697242,2242518,7212542,23197479,74609345, 239963764,771788146,2482278710,7983677420, 25677658553,82586271223,265619709074,854304581182, 2747673807690,8837259590742,28423008894139] |