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 | 25 |
| 5 | 86 |
| 6 | 278 |
| 7 | 1008 |
| 8 | 3689 |
| 9 | 13682 |
| 10 | 52296 |
| 11 | 197227 |
| 12 | 773129 |
| 13 | 3046086 |
| 14 | 12052354 |
| 15 | 48408204 |
| 16 | 193513935 |
| 17 | 787775457 |
| 18 | 3217911649 |
| 19 | 13176702706 |
| 20 | 54428194105 |
| 21 | 224345229457 |
| 22 | 934409171556 |
| 23 | 3901537710521 |
| 24 | 16317616662124 |
| 25 | 68629517947273 |
| 26 | 288349563162332 |
| 27 | 1219663317366366 |
| 28 | 5168604771907544 |
[1,1,3,8,25,86,278,1008,3689,13682,52296,197227, 773129,3046086,12052354,48408204,193513935, 787775457,3217911649,13176702706,54428194105, 224345229457,934409171556,3901537710521, 16317616662124,68629517947273,288349563162332, 1219663317366366,5168604771907544] |