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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 57 |
| 4 | 330 |
| 5 | 2436 |
| 6 | 23226 |
| 7 | 277389 |
| 8 | 3966534 |
| 9 | 65517210 |
| 10 | 1220999208 |
| 11 | 25279328958 |
| 12 | 575024187192 |
| 13 | 14247595540542 |
| 14 | 381846383109030 |
| 15 | 11004598454925405 |
| 16 | 339324532631899110 |
| 17 | 11146022446431209490 |
| 18 | 388535338484934710040 |
| 19 | 14324570939127320452350 |
| 20 | 556887682690152668745660 |
[1,3,12,57,330,2436,23226,277389,3966534,65517210, 1220999208,25279328958,575024187192, 14247595540542,381846383109030,11004598454925405, 339324532631899110,11146022446431209490, 388535338484934710040,14324570939127320452350, 556887682690152668745660] |