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 | 10 |
| 5 | 26 |
| 6 | 80 |
| 7 | 246 |
| 8 | 810 |
| 9 | 2704 |
| 10 | 9252 |
| 11 | 32066 |
| 12 | 112720 |
| 13 | 400024 |
| 14 | 1432860 |
| 15 | 5170604 |
| 16 | 18784170 |
| 17 | 68635478 |
| 18 | 252088496 |
| 19 | 930138522 |
| 20 | 3446167860 |
| 21 | 12815663844 |
| 22 | 47820447028 |
| 23 | 178987624514 |
| 24 | 671825133648 |
| 25 | 2528212128776 |
| 26 | 9536895064400 |
| 27 | 36054433810102 |
| 28 | 136583761444364 |
| 29 | 518401146543812 |
[1,1,2,4,10,26,80,246,810,2704,9252,32066,112720, 400024,1432860,5170604,18784170,68635478, 252088496,930138522,3446167860,12815663844, 47820447028,178987624514,671825133648, 2528212128776,9536895064400,36054433810102, 136583761444364,518401146543812] |