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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 13 |
| 3 | 37 |
| 4 | 126 |
| 5 | 385 |
| 6 | 1243 |
| 7 | 3924 |
| 8 | 12477 |
| 9 | 39625 |
| 10 | 125780 |
| 11 | 399527 |
| 12 | 1268481 |
| 13 | 4028320 |
| 14 | 12791471 |
| 15 | 40619227 |
| 16 | 128985178 |
| 17 | 409588149 |
| 18 | 1300636903 |
| 19 | 4130132236 |
| 20 | 13115120227 |
| 21 | 41646681705 |
| 22 | 132247843570 |
| 23 | 419949219621 |
| 24 | 1333536652989 |
| 25 | 4234607278278 |
[4,13,37,126,385,1243,3924,12477,39625,125780, 399527,1268481,4028320,12791471,40619227, 128985178,409588149,1300636903,4130132236, 13115120227,41646681705,132247843570,419949219621, 1333536652989,4234607278278] |