The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 13 |
| 3 | 57 |
| 4 | 259 |
| 5 | 1177 |
| 6 | 5367 |
| 7 | 24473 |
| 8 | 111631 |
| 9 | 509193 |
| 10 | 2322703 |
| 11 | 10595097 |
| 12 | 48330079 |
| 13 | 220460137 |
| 14 | 1005640527 |
| 15 | 4587282233 |
| 16 | 20925130111 |
| 17 | 95451085833 |
| 18 | 435405168943 |
| 19 | 1986123672537 |
| 20 | 9059808024799 |
| 21 | 41326792777897 |
| 22 | 188514347839887 |
| 23 | 859918153641593 |
| 24 | 3922562072528191 |
| 25 | 17892974055353673 |
[1,3,13,57,259,1177,5367,24473,111631,509193, 2322703,10595097,48330079,220460137,1005640527, 4587282233,20925130111,95451085833,435405168943, 1986123672537,9059808024799,41326792777897, 188514347839887,859918153641593,3922562072528191, 17892974055353673] |