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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 26 |
| 4 | 82 |
| 5 | 242 |
| 6 | 730 |
| 7 | 2186 |
| 8 | 6562 |
| 9 | 19682 |
| 10 | 59050 |
| 11 | 177146 |
| 12 | 531442 |
| 13 | 1594322 |
| 14 | 4782970 |
| 15 | 14348906 |
| 16 | 43046722 |
| 17 | 129140162 |
| 18 | 387420490 |
| 19 | 1162261466 |
| 20 | 3486784402 |
| 21 | 10460353202 |
| 22 | 31381059610 |
| 23 | 94143178826 |
| 24 | 282429536482 |
| 25 | 847288609442 |
| 26 | 2541865828330 |
| 27 | 7625597484986 |
[1,2,10,26,82,242,730,2186,6562,19682,59050, 177146,531442,1594322,4782970,14348906,43046722, 129140162,387420490,1162261466,3486784402, 10460353202,31381059610,94143178826,282429536482, 847288609442,2541865828330,7625597484986] |