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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 6 |
| 4 | 23 |
| 5 | 62 |
| 6 | 179 |
| 7 | 522 |
| 8 | 1503 |
| 9 | 4346 |
| 10 | 12563 |
| 11 | 36302 |
| 12 | 104919 |
| 13 | 303222 |
| 14 | 876323 |
| 15 | 2532626 |
| 16 | 7319423 |
| 17 | 21153522 |
| 18 | 61134819 |
| 19 | 176682902 |
| 20 | 510623063 |
| 21 | 1475728046 |
| 22 | 4264933203 |
| 23 | 12325885722 |
| 24 | 35622470879 |
| 25 | 102950851562 |
| 26 | 297533483123 |
| 27 | 859887725406 |
| 28 | 2485121649303 |
| 29 | 7182134864102 |
[-1,2,3,6,23,62,179,522,1503,4346,12563,36302, 104919,303222,876323,2532626,7319423,21153522, 61134819,176682902,510623063,1475728046, 4264933203,12325885722,35622470879,102950851562, 297533483123,859887725406,2485121649303, 7182134864102] |