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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 101 |
| 5 | 416 |
| 6 | 1787 |
| 7 | 7792 |
| 8 | 34645 |
| 9 | 155722 |
| 10 | 707795 |
| 11 | 3242515 |
| 12 | 14963665 |
| 13 | 69458000 |
| 14 | 324102287 |
| 15 | 1519028843 |
| 16 | 7147771981 |
| 17 | 33750528146 |
| 18 | 159860887355 |
| 19 | 759295147045 |
| 20 | 3615520821281 |
| 21 | 17255165910632 |
| 22 | 82521746019487 |
| 23 | 395404081034830 |
| 24 | 1897886817388201 |
| 25 | 9124229781131546 |
| 26 | 43930513066698367 |
| 27 | 211803668881914847 |
[1,2,7,25,101,416,1787,7792,34645,155722,707795, 3242515,14963665,69458000,324102287,1519028843, 7147771981,33750528146,159860887355,759295147045, 3615520821281,17255165910632,82521746019487, 395404081034830,1897886817388201,9124229781131546, 43930513066698367,211803668881914847] |