The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 11 |
| 4 | 39 |
| 5 | 105 |
| 6 | 335 |
| 7 | 965 |
| 8 | 2965 |
| 9 | 8755 |
| 10 | 26517 |
| 11 | 79047 |
| 12 | 238065 |
| 13 | 712347 |
| 14 | 2140473 |
| 15 | 6414555 |
| 16 | 19256535 |
| 17 | 57743865 |
| 18 | 173280215 |
| 19 | 519743405 |
| 20 | 1559414971 |
| 21 | 4677875401 |
| 22 | 14034331635 |
| 23 | 42101584041 |
| 24 | 126307456279 |
| 25 | 378916960525 |
| 26 | 1136761282175 |
| 27 | 3410263045325 |
| 28 | 10230829252575 |
[1,1,5,11,39,105,335,965,2965,8755,26517,79047, 238065,712347,2140473,6414555,19256535,57743865, 173280215,519743405,1559414971,4677875401, 14034331635,42101584041,126307456279,378916960525, 1136761282175,3410263045325,10230829252575] |