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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 46 |
| 5 | 163 |
| 6 | 711 |
| 7 | 2795 |
| 8 | 12428 |
| 9 | 51753 |
| 10 | 235649 |
| 11 | 1018677 |
| 12 | 4692842 |
| 13 | 20793843 |
| 14 | 96868626 |
| 15 | 437325625 |
| 16 | 2053558366 |
| 17 | 9396741255 |
| 18 | 44410201233 |
| 19 | 205466708855 |
| 20 | 976289490566 |
| 21 | 4555528967641 |
| 22 | 21739565731106 |
| 23 | 102161620436227 |
| 24 | 489367738092226 |
| 25 | 2313227779931447 |
| 26 | 11115478974146769 |
| 27 | 52801134542954409 |
[1,1,4,11,46,163,711,2795,12428,51753,235649, 1018677,4692842,20793843,96868626,437325625, 2053558366,9396741255,44410201233,205466708855, 976289490566,4555528967641,21739565731106, 102161620436227,489367738092226,2313227779931447, 11115478974146769,52801134542954409] |