The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 11 |
| 5 | 26 |
| 6 | 62 |
| 7 | 153 |
| 8 | 385 |
| 9 | 988 |
| 10 | 2573 |
| 11 | 6786 |
| 12 | 18084 |
| 13 | 48621 |
| 14 | 131718 |
| 15 | 359193 |
| 16 | 985185 |
| 17 | 2715972 |
| 18 | 7521567 |
| 19 | 20915256 |
| 20 | 58373586 |
| 21 | 163462815 |
| 22 | 459136809 |
| 23 | 1293223230 |
| 24 | 3651864606 |
| 25 | 10336625731 |
| 26 | 29321683082 |
| 27 | 83344398533 |
| 28 | 237344961291 |
[1,2,5,11,26,62,153,385,988,2573,6786,18084,48621, 131718,359193,985185,2715972,7521567,20915256, 58373586,163462815,459136809,1293223230, 3651864606,10336625731,29321683082,83344398533, 237344961291] |