The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 34 |
| 5 | 118 |
| 6 | 417 |
| 7 | 1495 |
| 8 | 5421 |
| 9 | 19838 |
| 10 | 73149 |
| 11 | 271453 |
| 12 | 1012872 |
| 13 | 3797228 |
| 14 | 14294518 |
| 15 | 54006728 |
| 16 | 204702328 |
| 17 | 778115558 |
| 18 | 2965409556 |
| 19 | 11327549778 |
| 20 | 43361526366 |
| 21 | 166306579062 |
| 22 | 638969153207 |
| 23 | 2458973656584 |
| 24 | 9477124288144 |
| 25 | 36576265716636 |
| 26 | 141344492073392 |
| 27 | 546860238004919 |
[1,3,10,34,118,417,1495,5421,19838,73149,271453, 1012872,3797228,14294518,54006728,204702328, 778115558,2965409556,11327549778,43361526366, 166306579062,638969153207,2458973656584, 9477124288144,36576265716636,141344492073392, 546860238004919] |