| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 1 |
| 5 | 6 |
| 6 | 22 |
| 7 | 99 |
| 8 | 451 |
| 9 | 2140 |
| 10 | 10396 |
| 11 | 51525 |
| 12 | 259429 |
| 13 | 1323362 |
| 14 | 6824434 |
| 15 | 35519687 |
| 16 | 186346759 |
| 17 | 984400760 |
| 18 | 5231789176 |
| 19 | 27954506505 |
| 20 | 150079713481 |
| 21 | 809181079294 |
| 22 | 4379654830222 |
| 23 | 23787413800491 |
| 24 | 129607968854731 |
| 25 | 708230837732436 |
| 26 | 3880366912218772 |
| 27 | 21312485647242829 |
| 28 | 117321536967959341 |
[1,1,6,22,99,451,2140,10396,51525,259429,1323362, 6824434,35519687,186346759,984400760,5231789176, 27954506505,150079713481,809181079294, 4379654830222,23787413800491,129607968854731, 708230837732436,3880366912218772, 21312485647242829,117321536967959341] |