| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 22 |
| 6 | 61 |
| 7 | 171 |
| 8 | 483 |
| 9 | 1373 |
| 10 | 3923 |
| 11 | 11257 |
| 12 | 32418 |
| 13 | 93644 |
| 14 | 271219 |
| 15 | 787333 |
| 16 | 2290200 |
| 17 | 6673662 |
| 18 | 19478091 |
| 19 | 56930961 |
| 20 | 166613280 |
| 21 | 488176938 |
| 22 | 1431878079 |
| 23 | 4203938697 |
| 24 | 12353600427 |
| 25 | 36331804089 |
| 26 | 106932444885 |
| 27 | 314946659951 |
| 28 | 928213563878 |
[1,1,1,3,8,22,61,171,483,1373,3923,11257,32418, 93644,271219,787333,2290200,6673662,19478091, 56930961,166613280,488176938,1431878079, 4203938697,12353600427,36331804089,106932444885, 314946659951,928213563878] |