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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 13 |
| 7 | 35 |
| 8 | 97 |
| 9 | 275 |
| 10 | 794 |
| 11 | 2327 |
| 12 | 6905 |
| 13 | 20705 |
| 14 | 62642 |
| 15 | 190987 |
| 16 | 586219 |
| 17 | 1810011 |
| 18 | 5617914 |
| 19 | 17518463 |
| 20 | 54857506 |
| 21 | 172431935 |
| 22 | 543861219 |
| 23 | 1720737981 |
| 24 | 5459867166 |
| 25 | 17369553427 |
| 26 | 55391735455 |
| 27 | 177040109419 |
| 28 | 567019562429 |
| 29 | 1819536774089 |
[2,1,1,2,5,13,35,97,275,794,2327,6905,20705,62642, 190987,586219,1810011,5617914,17518463,54857506, 172431935,543861219,1720737981,5459867166, 17369553427,55391735455,177040109419,567019562429, 1819536774089] |