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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 14 |
| 4 | 42 |
| 5 | 130 |
| 6 | 412 |
| 7 | 1326 |
| 8 | 4318 |
| 9 | 14188 |
| 10 | 46950 |
| 11 | 156258 |
| 12 | 522523 |
| 13 | 1754254 |
| 14 | 5909419 |
| 15 | 19964450 |
| 16 | 67618388 |
| 17 | 229526054 |
| 18 | 780633253 |
| 19 | 2659600616 |
| 20 | 9075301990 |
| 21 | 31010850632 |
| 22 | 106100239080 |
| 23 | 363428599306 |
| 24 | 1246172974048 |
| 25 | 4277163883744 |
| 26 | 14693260749888 |
| 27 | 50516757992258 |
[1,2,5,14,42,130,412,1326,4318,14188,46950,156258, 522523,1754254,5909419,19964450,67618388, 229526054,780633253,2659600616,9075301990, 31010850632,106100239080,363428599306, 1246172974048,4277163883744,14693260749888, 50516757992258] |