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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 21 |
| 4 | 93 |
| 5 | 334 |
| 6 | 1545 |
| 7 | 5904 |
| 8 | 28361 |
| 9 | 113885 |
| 10 | 551115 |
| 11 | 2267035 |
| 12 | 11116928 |
| 13 | 46792329 |
| 14 | 229966829 |
| 15 | 980712270 |
| 16 | 4849282854 |
| 17 | 20956092385 |
| 18 | 103706253002 |
| 19 | 451920681361 |
| 20 | 2243783211929 |
| 21 | 9862687093128 |
| 22 | 48985163274870 |
| 23 | 216579668572023 |
| 24 | 1077789377046301 |
| 25 | 4794449369040784 |
| 26 | 23862905082085041 |
| 27 | 106615213319244750 |
[1,2,7,21,93,334,1545,5904,28361,113885,551115, 2267035,11116928,46792329,229966829,980712270, 4849282854,20956092385,103706253002,451920681361, 2243783211929,9862687093128,48985163274870, 216579668572023,1077789377046301,4794449369040784, 23862905082085041,106615213319244750] |