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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 | 23197478 |
| 15 | 74609338 |
| 16 | 239963729 |
| 17 | 771787993 |
| 18 | 2482278087 |
| 19 | 7983674995 |
| 20 | 25677649398 |
| 21 | 82586237418 |
| 22 | 265619586324 |
| 23 | 854304141280 |
| 24 | 2747672247776 |
[2,6,19,61,196,630,2026,6516,20957,67403,216786, 697242,2242518,7212542,23197478,74609338, 239963729,771787993,2482278087,7983674995, 25677649398,82586237418,265619586324,854304141280, 2747672247776] |