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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 17 |
| 5 | 53 |
| 6 | 155 |
| 7 | 429 |
| 8 | 1210 |
| 9 | 3457 |
| 10 | 9948 |
| 11 | 28528 |
| 12 | 81636 |
| 13 | 233344 |
| 14 | 667390 |
| 15 | 1909626 |
| 16 | 5464861 |
| 17 | 15637212 |
| 18 | 44741387 |
| 19 | 128011961 |
| 20 | 366269502 |
| 21 | 1047988385 |
| 22 | 2998562936 |
| 23 | 8579622673 |
| 24 | 24548350663 |
| 25 | 70238679485 |
| 26 | 200969734254 |
| 27 | 575022887468 |
[1,2,5,17,53,155,429,1210,3457,9948,28528,81636, 233344,667390,1909626,5464861,15637212,44741387, 128011961,366269502,1047988385,2998562936, 8579622673,24548350663,70238679485,200969734254, 575022887468] |