The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 9 |
| 3 | 33 |
| 4 | 159 |
| 5 | 671 |
| 6 | 3288 |
| 7 | 14719 |
| 8 | 72664 |
| 9 | 335880 |
| 10 | 1664988 |
| 11 | 7849149 |
| 12 | 39004188 |
| 13 | 186294948 |
| 14 | 927213201 |
| 15 | 4469530443 |
| 16 | 22269520555 |
| 17 | 108073079585 |
| 18 | 538890342551 |
| 19 | 2628561459138 |
| 20 | 13114310579949 |
| 21 | 64221071659033 |
| 22 | 320544468838524 |
| 23 | 1574624610642784 |
| 24 | 7861912554105647 |
| 25 | 38717644728189914 |
| 26 | 193361258767889412 |
[1,2,9,33,159,671,3288,14719,72664,335880,1664988, 7849149,39004188,186294948,927213201,4469530443, 22269520555,108073079585,538890342551, 2628561459138,13114310579949,64221071659033, 320544468838524,1574624610642784,7861912554105647, 38717644728189914,193361258767889412] |