The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 13 |
| 5 | 41 |
| 6 | 176 |
| 7 | 722 |
| 8 | 3774 |
| 9 | 18958 |
| 10 | 116302 |
| 11 | 687182 |
| 12 | 4812226 |
| 13 | 32541874 |
| 14 | 255274826 |
| 15 | 1938568634 |
| 16 | 16798483589 |
| 17 | 141220228149 |
| 18 | 1337121257864 |
| 19 | 12305678519102 |
| 20 | 126208299343263 |
| 21 | 1260257489267963 |
| 22 | 13901541357573146 |
| 23 | 149520289244078172 |
| 24 | 1763398965493327476 |
[1,1,2,4,13,41,176,722,3774,18958,116302,687182, 4812226,32541874,255274826,1938568634,16798483589, 141220228149,1337121257864,12305678519102, 126208299343263,1260257489267963, 13901541357573146,149520289244078172, 1763398965493327476] |