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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 54 |
| 5 | 191 |
| 6 | 708 |
| 7 | 2691 |
| 8 | 10500 |
| 9 | 41709 |
| 10 | 167949 |
| 11 | 686327 |
| 12 | 2833422 |
| 13 | 11805214 |
| 14 | 49617037 |
| 15 | 209963526 |
| 16 | 894400402 |
| 17 | 3831980642 |
| 18 | 16499883222 |
| 19 | 71390792327 |
| 20 | 310181111919 |
| 21 | 1352902241363 |
| 22 | 5922364156483 |
| 23 | 26008930393279 |
| 24 | 114573064355346 |
| 25 | 506138029794659 |
| 26 | 2241723481851415 |
| 27 | 9953362142887318 |
[1,2,5,16,54,191,708,2691,10500,41709,167949, 686327,2833422,11805214,49617037,209963526, 894400402,3831980642,16499883222,71390792327, 310181111919,1352902241363,5922364156483, 26008930393279,114573064355346,506138029794659, 2241723481851415,9953362142887318] |