| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 33 |
| 4 | 129 |
| 5 | 516 |
| 6 | 2150 |
| 7 | 9129 |
| 8 | 39208 |
| 9 | 170844 |
| 10 | 751739 |
| 11 | 3329775 |
| 12 | 14854617 |
| 13 | 66658383 |
| 14 | 300429493 |
| 15 | 1359788478 |
| 16 | 6178043489 |
| 17 | 28156202058 |
| 18 | 128688253311 |
| 19 | 589725931525 |
| 20 | 2708660600493 |
| 21 | 12467109806982 |
| 22 | 57493840683072 |
| 23 | 265605179665083 |
| 24 | 1228989585714965 |
| 25 | 5695220219094839 |
| 26 | 26428445184643521 |
| 27 | 122796644702539179 |
[1,3,9,33,129,516,2150,9129,39208,170844,751739, 3329775,14854617,66658383,300429493,1359788478, 6178043489,28156202058,128688253311,589725931525, 2708660600493,12467109806982,57493840683072, 265605179665083,1228989585714965,5695220219094839, 26428445184643521,122796644702539179] |