The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 53 |
| 6 | 201 |
| 7 | 735 |
| 8 | 2865 |
| 9 | 11311 |
| 10 | 45866 |
| 11 | 189465 |
| 12 | 796172 |
| 13 | 3381641 |
| 14 | 14561199 |
| 15 | 63187193 |
| 16 | 276872754 |
| 17 | 1222044791 |
| 18 | 5430760602 |
| 19 | 24286138255 |
| 20 | 109201747174 |
| 21 | 493481357555 |
| 22 | 2240419937667 |
| 23 | 10213170677321 |
| 24 | 46739370653550 |
| 25 | 214646461546109 |
| 26 | 988964308208578 |
| 27 | 4570386968516601 |
| 28 | 21180640601186075 |
[1,1,2,5,16,53,201,735,2865,11311,45866,189465, 796172,3381641,14561199,63187193,276872754, 1222044791,5430760602,24286138255,109201747174, 493481357555,2240419937667,10213170677321, 46739370653550,214646461546109,988964308208578, 4570386968516601,21180640601186075] |