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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 11 |
| 4 | 21 |
| 5 | 44 |
| 6 | 101 |
| 7 | 247 |
| 8 | 626 |
| 9 | 1615 |
| 10 | 4201 |
| 11 | 10968 |
| 12 | 28681 |
| 13 | 75051 |
| 14 | 196446 |
| 15 | 514259 |
| 16 | 1346301 |
| 17 | 3524612 |
| 18 | 9227501 |
| 19 | 24157855 |
| 20 | 63246026 |
| 21 | 165580183 |
| 22 | 433494481 |
| 23 | 1134903216 |
| 24 | 2971215121 |
| 25 | 7778742099 |
| 26 | 20365011126 |
| 27 | 53316291227 |
| 28 | 139583862501 |
| 29 | 365435296220 |
| 30 | 956722026101 |
[1,3,6,11,21,44,101,247,626,1615,4201,10968,28681, 75051,196446,514259,1346301,3524612,9227501, 24157855,63246026,165580183,433494481,1134903216, 2971215121,7778742099,20365011126,53316291227, 139583862501,365435296220,956722026101] |