The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 44 |
| 4 | 134 |
| 5 | 468 |
| 6 | 1524 |
| 7 | 4584 |
| 8 | 13862 |
| 9 | 40566 |
| 10 | 114880 |
| 11 | 321052 |
| 12 | 879092 |
| 13 | 2360156 |
| 14 | 6248864 |
| 15 | 16297384 |
| 16 | 41902454 |
| 17 | 106437600 |
| 18 | 267149022 |
| 19 | 662979572 |
| 20 | 1628437160 |
| 21 | 3960377672 |
| 22 | 9541519732 |
| 23 | 22786066280 |
| 24 | 53958062564 |
| 25 | 126750346970 |
| 26 | 295476011176 |
| 27 | 683776368416 |
| 28 | 1571299804688 |
[1,2,10,44,134,468,1524,4584,13862,40566,114880, 321052,879092,2360156,6248864,16297384,41902454, 106437600,267149022,662979572,1628437160, 3960377672,9541519732,22786066280,53958062564, 126750346970,295476011176,683776368416, 1571299804688] |