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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 35 |
| 5 | 124 |
| 6 | 505 |
| 7 | 1986 |
| 8 | 8332 |
| 9 | 34590 |
| 10 | 148477 |
| 11 | 636316 |
| 12 | 2779009 |
| 13 | 12157264 |
| 14 | 53805721 |
| 15 | 238768325 |
| 16 | 1067794767 |
| 17 | 4788480698 |
| 18 | 21592411576 |
| 19 | 97615331419 |
| 20 | 443124695004 |
| 21 | 2016183557312 |
| 22 | 9202926348780 |
| 23 | 42092256924557 |
| 24 | 193015496297659 |
| 25 | 886662045847162 |
| 26 | 4081658522126465 |
| 27 | 18819149960554654 |
[1,1,3,9,35,124,505,1986,8332,34590,148477,636316, 2779009,12157264,53805721,238768325,1067794767, 4788480698,21592411576,97615331419,443124695004, 2016183557312,9202926348780,42092256924557, 193015496297659,886662045847162,4081658522126465, 18819149960554654] |