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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 9 |
| 5 | 21 |
| 6 | 52 |
| 7 | 127 |
| 8 | 313 |
| 9 | 778 |
| 10 | 1941 |
| 11 | 4863 |
| 12 | 12228 |
| 13 | 30837 |
| 14 | 77967 |
| 15 | 197574 |
| 16 | 501657 |
| 17 | 1275987 |
| 18 | 3250618 |
| 19 | 8292703 |
| 20 | 21182509 |
| 21 | 54169966 |
| 22 | 138674031 |
| 23 | 355343469 |
| 24 | 911347684 |
| 25 | 2339226871 |
| 26 | 6008781637 |
| 27 | 15445521202 |
| 28 | 39728258103 |
| 29 | 102248793573 |
| 30 | 263306364822 |
| 31 | 678411876729 |
| 32 | 1748800672089 |
[2,1,1,4,9,21,52,127,313,778,1941,4863,12228, 30837,77967,197574,501657,1275987,3250618,8292703, 21182509,54169966,138674031,355343469,911347684, 2339226871,6008781637,15445521202,39728258103, 102248793573,263306364822,678411876729, 1748800672089] |