The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 53 |
| 5 | 275 |
| 6 | 878 |
| 7 | 2031 |
| 8 | 2909 |
| 9 | 141663 |
| 10 | 144572 |
| 11 | 430807 |
| 12 | 1436993 |
| 13 | 7615772 |
| 14 | 39515853 |
| 15 | 126163331 |
| 16 | 291842515 |
| 17 | 418005846 |
| 18 | 20356123123 |
| 19 | 20774128969 |
| 20 | 61904381061 |
| 21 | 206487272152 |
| 22 | 1094340741821 |
| 23 | 5678190981257 |
| 24 | 18128913685592 |
| 25 | 41936018352441 |
| 26 | 60064932038033 |
[1,1,3,10,53,275,878,2031,2909,141663,144572, 430807,1436993,7615772,39515853,126163331, 291842515,418005846,20356123123,20774128969, 61904381061,206487272152,1094340741821, 5678190981257,18128913685592,41936018352441, 60064932038033] |