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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 44 |
| 5 | 158 |
| 6 | 658 |
| 7 | 2607 |
| 8 | 11193 |
| 9 | 46595 |
| 10 | 204255 |
| 11 | 875999 |
| 12 | 3896188 |
| 13 | 17047797 |
| 14 | 76627162 |
| 15 | 340148317 |
| 16 | 1541155940 |
| 17 | 6915715632 |
| 18 | 31530564726 |
| 19 | 142683439604 |
| 20 | 653825245219 |
| 21 | 2978569580564 |
| 22 | 13705939356429 |
| 23 | 62778713274257 |
| 24 | 289894469530054 |
| 25 | 1333800098361492 |
| 26 | 6177646452734974 |
| 27 | 28530308252975460 |
[1,1,4,11,44,158,658,2607,11193,46595,204255, 875999,3896188,17047797,76627162,340148317, 1541155940,6915715632,31530564726,142683439604, 653825245219,2978569580564,13705939356429, 62778713274257,289894469530054,1333800098361492, 6177646452734974,28530308252975460] |