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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 86 |
| 5 | 324 |
| 6 | 1299 |
| 7 | 5248 |
| 8 | 21803 |
| 9 | 91109 |
| 10 | 386870 |
| 11 | 1652908 |
| 12 | 7140192 |
| 13 | 31015614 |
| 14 | 135755899 |
| 15 | 596894225 |
| 16 | 2639027048 |
| 17 | 11712554874 |
| 18 | 52208189271 |
| 19 | 233481867841 |
| 20 | 1047793276565 |
| 21 | 4715377052267 |
| 22 | 21281091083730 |
| 23 | 96276529269418 |
| 24 | 436603412361372 |
| 25 | 1984114640043230 |
| 26 | 9035173400355720 |
| 27 | 41219771952879434 |
[1,2,7,23,86,324,1299,5248,21803,91109,386870, 1652908,7140192,31015614,135755899,596894225, 2639027048,11712554874,52208189271,233481867841, 1047793276565,4715377052267,21281091083730, 96276529269418,436603412361372,1984114640043230, 9035173400355720,41219771952879434] |