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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 17 |
| 5 | 51 |
| 6 | 171 |
| 7 | 589 |
| 8 | 2049 |
| 9 | 7409 |
| 10 | 27508 |
| 11 | 103052 |
| 12 | 392031 |
| 13 | 1517989 |
| 14 | 5935172 |
| 15 | 23393990 |
| 16 | 93204843 |
| 17 | 374588839 |
| 18 | 1514534730 |
| 19 | 6164304590 |
| 20 | 25261163401 |
| 21 | 104062614425 |
| 22 | 430672375871 |
| 23 | 1791323699173 |
| 24 | 7484537175001 |
| 25 | 31389035415355 |
| 26 | 132129910409698 |
| 27 | 558261805574402 |
| 28 | 2366357769309447 |
[1,1,2,6,17,51,171,589,2049,7409,27508,103052, 392031,1517989,5935172,23393990,93204843, 374588839,1514534730,6164304590,25261163401, 104062614425,430672375871,1791323699173, 7484537175001,31389035415355,132129910409698, 558261805574402,2366357769309447] |