The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 49 |
| 5 | 170 |
| 6 | 619 |
| 7 | 2316 |
| 8 | 8807 |
| 9 | 34064 |
| 10 | 133999 |
| 11 | 533104 |
| 12 | 2138252 |
| 13 | 8645140 |
| 14 | 35208465 |
| 15 | 144247477 |
| 16 | 594033854 |
| 17 | 2457732830 |
| 18 | 10209721069 |
| 19 | 42566281522 |
| 20 | 178065201645 |
| 21 | 747148601038 |
| 22 | 3143382071022 |
| 23 | 13257330682170 |
| 24 | 56042111023881 |
| 25 | 237404352309975 |
| 26 | 1007627536356778 |
| 27 | 4284395710494869 |
[1,2,5,15,49,170,619,2316,8807,34064,133999, 533104,2138252,8645140,35208465,144247477, 594033854,2457732830,10209721069,42566281522, 178065201645,747148601038,3143382071022, 13257330682170,56042111023881,237404352309975, 1007627536356778,4284395710494869] |