The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 28 |
| 5 | 91 |
| 6 | 357 |
| 7 | 1316 |
| 8 | 5290 |
| 9 | 21137 |
| 10 | 87905 |
| 11 | 364034 |
| 12 | 1561508 |
| 13 | 6634870 |
| 14 | 29020984 |
| 15 | 126046450 |
| 16 | 559099248 |
| 17 | 2469187687 |
| 18 | 11084955557 |
| 19 | 49574819823 |
| 20 | 224824650873 |
| 21 | 1015850981738 |
| 22 | 4645039658822 |
| 23 | 21172021133032 |
| 24 | 97474508273022 |
| 25 | 447579684854340 |
| 26 | 2072778400834434 |
| 27 | 9577522969707324 |
| 28 | 44582241806569082 |
[1,1,3,8,28,91,357,1316,5290,21137,87905,364034, 1561508,6634870,29020984,126046450,559099248, 2469187687,11084955557,49574819823,224824650873, 1015850981738,4645039658822,21172021133032, 97474508273022,447579684854340,2072778400834434, 9577522969707324,44582241806569082] |