| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 22 |
| 6 | 65 |
| 7 | 212 |
| 8 | 697 |
| 9 | 2372 |
| 10 | 8179 |
| 11 | 28703 |
| 12 | 101851 |
| 13 | 365393 |
| 14 | 1322034 |
| 15 | 4820378 |
| 16 | 17691018 |
| 17 | 65306700 |
| 18 | 242317423 |
| 19 | 903242615 |
| 20 | 3380707920 |
| 21 | 12700575742 |
| 22 | 47874113728 |
| 23 | 181013422393 |
| 24 | 686341240781 |
| 25 | 2609093456212 |
| 26 | 9941953711409 |
[1,1,1,3,7,22,65,212,697,2372,8179,28703,101851, 365393,1322034,4820378,17691018,65306700, 242317423,903242615,3380707920,12700575742, 47874113728,181013422393,686341240781, 2609093456212,9941953711409] |