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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 19 |
| 5 | 61 |
| 6 | 196 |
| 7 | 629 |
| 8 | 2017 |
| 9 | 6466 |
| 10 | 20727 |
| 11 | 66441 |
| 12 | 212980 |
| 13 | 682721 |
| 14 | 2188509 |
| 15 | 7015418 |
| 16 | 22488411 |
| 17 | 72088165 |
| 18 | 231083620 |
| 19 | 740754589 |
| 20 | 2374540265 |
| 21 | 7611753682 |
| 22 | 24400004911 |
| 23 | 78215909841 |
| 24 | 250726529556 |
| 25 | 803721298537 |
| 26 | 2576384425157 |
| 27 | 8258779154250 |
| 28 | 26474089989299 |
[1,2,6,19,61,196,629,2017,6466,20727,66441,212980, 682721,2188509,7015418,22488411,72088165, 231083620,740754589,2374540265,7611753682, 24400004911,78215909841,250726529556,803721298537, 2576384425157,8258779154250,26474089989299] |