The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 26 |
| 4 | 97 |
| 5 | 362 |
| 6 | 1351 |
| 7 | 5042 |
| 8 | 18817 |
| 9 | 70226 |
| 10 | 262087 |
| 11 | 978122 |
| 12 | 3650401 |
| 13 | 13623482 |
| 14 | 50843527 |
| 15 | 189750626 |
| 16 | 708158977 |
| 17 | 2642885282 |
| 18 | 9863382151 |
| 19 | 36810643322 |
| 20 | 137379191137 |
| 21 | 512706121226 |
| 22 | 1913445293767 |
| 23 | 7141075053842 |
| 24 | 26650854921601 |
| 25 | 99462344632562 |
| 26 | 371198523608647 |
[1,2,7,26,97,362,1351,5042,18817,70226,262087, 978122,3650401,13623482,50843527,189750626, 708158977,2642885282,9863382151,36810643322, 137379191137,512706121226,1913445293767, 7141075053842,26650854921601,99462344632562, 371198523608647] |