| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 6 |
| 4 | 15 |
| 5 | 27 |
| 6 | 58 |
| 7 | 112 |
| 8 | 229 |
| 9 | 453 |
| 10 | 912 |
| 11 | 1818 |
| 12 | 3643 |
| 13 | 7279 |
| 14 | 14566 |
| 15 | 29124 |
| 16 | 58257 |
| 17 | 116505 |
| 18 | 233020 |
| 19 | 466030 |
| 20 | 932071 |
| 21 | 1864131 |
| 22 | 3728274 |
| 23 | 7456536 |
| 24 | 14913085 |
| 25 | 29826157 |
| 26 | 59652328 |
| 27 | 119304642 |
| 28 | 238609299 |
[1,1,4,6,15,27,58,112,229,453,912,1818,3643,7279, 14566,29124,58257,116505,233020,466030,932071, 1864131,3728274,7456536,14913085,29826157, 59652328,119304642,238609299] |