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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 18 |
| 5 | 38 |
| 6 | 88 |
| 7 | 192 |
| 8 | 450 |
| 9 | 1002 |
| 10 | 2364 |
| 11 | 5336 |
| 12 | 12642 |
| 13 | 28814 |
| 14 | 68464 |
| 15 | 157184 |
| 16 | 374274 |
| 17 | 864146 |
| 18 | 2060980 |
| 19 | 4780008 |
| 20 | 11414898 |
| 21 | 26572086 |
| 22 | 63521352 |
| 23 | 148321344 |
| 24 | 354870594 |
| 25 | 830764794 |
| 26 | 1989102444 |
| 27 | 4666890936 |
| 28 | 11180805570 |
| 29 | 26283115038 |
[1,2,4,8,18,38,88,192,450,1002,2364,5336,12642, 28814,68464,157184,374274,864146,2060980,4780008, 11414898,26572086,63521352,148321344,354870594, 830764794,1989102444,4666890936,11180805570, 26283115038] |