| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 1 |
| 6 | 2 |
| 7 | 3 |
| 8 | 10 |
| 9 | 21 |
| 10 | 83 |
| 11 | 298 |
| 12 | 1339 |
| 13 | 6049 |
| 14 | 29765 |
| 15 | 148842 |
| 16 | 770267 |
| 17 | 4054539 |
| 18 | 21743705 |
| 19 | 118237471 |
| 20 | 651370528 |
| 21 | 3628421181 |
| 22 | 20416662314 |
| 23 | 115919209155 |
| 24 | 663548898942 |
| 25 | 3826577783917 |
| 26 | 22217382001865 |
| 27 | 129800215435088 |
[1,1,2,3,10,21,83,298,1339,6049,29765,148842, 770267,4054539,21743705,118237471,651370528, 3628421181,20416662314,115919209155,663548898942, 3826577783917,22217382001865,129800215435088] |