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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 30 |
| 5 | 104 |
| 6 | 418 |
| 7 | 1619 |
| 8 | 6811 |
| 9 | 27995 |
| 10 | 121479 |
| 11 | 518165 |
| 12 | 2298497 |
| 13 | 10057101 |
| 14 | 45342297 |
| 15 | 202127226 |
| 16 | 922674852 |
| 17 | 4172053826 |
| 18 | 19231818364 |
| 19 | 87941092870 |
| 20 | 408591525432 |
| 21 | 1885356748718 |
| 22 | 8816855295648 |
| 23 | 40987943515892 |
| 24 | 192726338718178 |
| 25 | 901557225420892 |
| 26 | 4258807073126730 |
| 27 | 20028060258669392 |
[1,1,3,8,30,104,418,1619,6811,27995,121479,518165, 2298497,10057101,45342297,202127226,922674852, 4172053826,19231818364,87941092870,408591525432, 1885356748718,8816855295648,40987943515892, 192726338718178,901557225420892,4258807073126730, 20028060258669392] |