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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 20 |
| 6 | 47 |
| 7 | 110 |
| 8 | 251 |
| 9 | 564 |
| 10 | 1251 |
| 11 | 2750 |
| 12 | 5994 |
| 13 | 12978 |
| 14 | 27934 |
| 15 | 59825 |
| 16 | 127565 |
| 17 | 270959 |
| 18 | 573575 |
| 19 | 1210466 |
| 20 | 2547562 |
| 21 | 5348385 |
| 22 | 11203292 |
| 23 | 23419629 |
| 24 | 48865346 |
| 25 | 101782870 |
| 26 | 211670094 |
| 27 | 439548898 |
| 28 | 911515214 |
| 29 | 1887865266 |
| 30 | 3905400206 |
| 31 | 8070139762 |
| 32 | 16658958223 |
| 33 | 34355273843 |
[0,1,3,8,20,47,110,251,564,1251,2750,5994,12978, 27934,59825,127565,270959,573575,1210466,2547562, 5348385,11203292,23419629,48865346,101782870, 211670094,439548898,911515214,1887865266, 3905400206,8070139762,16658958223,34355273843] |