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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 28 |
| 5 | 93 |
| 6 | 315 |
| 7 | 1092 |
| 8 | 3855 |
| 9 | 13797 |
| 10 | 49932 |
| 11 | 182361 |
| 12 | 671088 |
| 13 | 2485513 |
| 14 | 9256395 |
| 15 | 34636833 |
| 16 | 130150524 |
| 17 | 490853405 |
| 18 | 1857283155 |
| 19 | 7048151460 |
| 20 | 26817356775 |
| 21 | 102280151421 |
| 22 | 390937467653 |
| 23 | 1497207322929 |
| 24 | 5744387279809 |
| 25 | 22076468761620 |
| 26 | 84973577874915 |
| 27 | 327534518354217 |
[1,3,9,28,93,315,1092,3855,13797,49932,182361, 671088,2485513,9256395,34636833,130150524, 490853405,1857283155,7048151460,26817356775, 102280151421,390937467653,1497207322929, 5744387279809,22076468761620,84973577874915, 327534518354217] |