| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 11 |
| 3 | 25 |
| 4 | 52 |
| 5 | 103 |
| 6 | 198 |
| 7 | 377 |
| 8 | 717 |
| 9 | 1366 |
| 10 | 2609 |
| 11 | 5016 |
| 12 | 9707 |
| 13 | 18882 |
| 14 | 36864 |
| 15 | 72151 |
| 16 | 141739 |
| 17 | 279335 |
| 18 | 551783 |
| 19 | 1091651 |
| 20 | 2161875 |
| 21 | 4284004 |
| 22 | 8501136 |
| 23 | 16890969 |
| 24 | 33591903 |
| 25 | 66847031 |
| 26 | 133075695 |
| 27 | 264984011 |
[1,4,11,25,52,103,198,377,717,1366,2609,5016,9707, 18882,36864,72151,141739,279335,551783,1091651, 2161875,4284004,8501136,16890969,33591903, 66847031,133075695,264984011] |