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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 28 |
| 6 | 78 |
| 7 | 213 |
| 8 | 598 |
| 9 | 1670 |
| 10 | 4723 |
| 11 | 13356 |
| 12 | 37986 |
| 13 | 108193 |
| 14 | 309169 |
| 15 | 884923 |
| 16 | 2538369 |
| 17 | 7292170 |
| 18 | 20982220 |
| 19 | 60451567 |
| 20 | 174385063 |
| 21 | 503600439 |
| 22 | 1455827279 |
| 23 | 4212464112 |
| 24 | 12199373350 |
| 25 | 35357580112 |
| 26 | 102552754000 |
| 27 | 297651592188 |
| 28 | 864460682777 |
| 29 | 2512115979800 |
| 30 | 7304240074858 |
[1,2,4,11,28,78,213,598,1670,4723,13356,37986, 108193,309169,884923,2538369,7292170,20982220, 60451567,174385063,503600439,1455827279, 4212464112,12199373350,35357580112,102552754000, 297651592188,864460682777,2512115979800, 7304240074858] |