The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 12 |
| 4 | 29 |
| 5 | 68 |
| 6 | 163 |
| 7 | 376 |
| 8 | 895 |
| 9 | 2046 |
| 10 | 4845 |
| 11 | 11018 |
| 12 | 25997 |
| 13 | 58930 |
| 14 | 138699 |
| 15 | 313756 |
| 16 | 737185 |
| 17 | 1665342 |
| 18 | 3908059 |
| 19 | 8820378 |
| 20 | 20681069 |
| 21 | 46646884 |
| 22 | 109305969 |
| 23 | 246433804 |
| 24 | 577207671 |
| 25 | 1300924056 |
| 26 | 3046122447 |
| 27 | 6863883442 |
| 28 | 16068177699 |
[1,2,5,12,29,68,163,376,895,2046,4845,11018,25997, 58930,138699,313756,737185,1665342,3908059, 8820378,20681069,46646884,109305969,246433804, 577207671,1300924056,3046122447,6863883442, 16068177699] |