The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 8 |
| 4 | 33 |
| 5 | 96 |
| 6 | 365 |
| 7 | 1256 |
| 8 | 4692 |
| 9 | 17453 |
| 10 | 66767 |
| 11 | 256482 |
| 12 | 1001942 |
| 13 | 3926568 |
| 14 | 15583714 |
| 15 | 62184933 |
| 16 | 249869139 |
| 17 | 1009404100 |
| 18 | 4096851309 |
| 19 | 16704180961 |
| 20 | 68417152583 |
| 21 | 281223053247 |
| 22 | 1160052280209 |
| 23 | 4799545992873 |
| 24 | 19914517613967 |
| 25 | 82863777810256 |
| 26 | 345665800672430 |
| 27 | 1445293788790669 |
| 28 | 6056038669330241 |
[1,1,4,8,33,96,365,1256,4692,17453,66767,256482, 1001942,3926568,15583714,62184933,249869139, 1009404100,4096851309,16704180961,68417152583, 281223053247,1160052280209,4799545992873, 19914517613967,82863777810256,345665800672430, 1445293788790669,6056038669330241] |