| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 48 |
| 8 | 114 |
| 9 | 278 |
| 10 | 676 |
| 11 | 1653 |
| 12 | 4027 |
| 13 | 9816 |
| 14 | 23843 |
| 15 | 57833 |
| 16 | 139908 |
| 17 | 337856 |
| 18 | 814127 |
| 19 | 1958524 |
| 20 | 4703322 |
| 21 | 11278027 |
| 22 | 27003707 |
| 23 | 64571463 |
| 24 | 154207616 |
| 25 | 367841733 |
| 26 | 876450881 |
| 27 | 2086098057 |
| 28 | 4960230005 |
| 29 | 11782852600 |
| 30 | 27963874395 |
| 31 | 66307010599 |
[1,1,1,2,4,9,20,48,114,278,676,1653,4027,9816, 23843,57833,139908,337856,814127,1958524,4703322, 11278027,27003707,64571463,154207616,367841733, 876450881,2086098057,4960230005,11782852600, 27963874395,66307010599] |